If 0.090 mole of solid NaOH is added to 1.0 liter of 0.180 m [tex]CH_3COOH[/tex]. The pH of the resulting solution is 4.74.
To solve this problem, we need to use the equation for the dissociation of acetic acid:
[tex]CH_3COOH + H_2O[/tex]⇌ [tex]CH_3COO^{-} + H_3O^+[/tex]
The addition of solid NaOH will react with the acetic acid to form sodium acetate and water:
[tex]CH_3COOH + NaOH[/tex] → [tex]CH_3COO^{-} Na^{+} + H_2O[/tex]
To calculate the pH of the resulting solution, we need to determine the new concentrations of [tex]CH_3COOH[/tex]and [tex]CH_3COO^-[/tex]. We can use the initial concentration of [tex]CH_3COOH[/tex]and the amount of NaOH added to calculate the new concentration of [tex]CH_3COOH[/tex]:
moles of [tex]CH_3COOH[/tex]= initial concentration x volume = 0.180 M x 1.0 L = 0.180 moles
moles of NaOH = 0.090 moles
moles of [tex]CH_3COOH[/tex]remaining = 0.180 moles - 0.090 moles = 0.090 moles
volume of solution = 1.0 L + 0.090 L = 1.090 L
new concentration of [tex]CH_3COOH[/tex]= moles / volume = 0.090 moles / 1.090 L = 0.0826 M
Since NaOH is a strong base, it will completely dissociate in water to form [tex]Na^+[/tex] and [tex]OH^-[/tex]. The [tex]OH^-[/tex] ions will react with the remaining [tex]CH_3COOH[/tex]to form [tex]CH_3COO^-[/tex], so the new concentration of [tex]CH_3COO^-[/tex] will be equal to the moles of NaOH added:
new concentration of [tex]CH_3COO^-[/tex] = 0.090 moles / 1.090 L = 0.0826 M
Now we can use the equilibrium expression for the dissociation of acetic acid to calculate the pH of the buffer:
[tex]Ka = [CH_3COO^{-}][H_3O^{+}] / [CH_3COOH]\\[H_3O^{+}] = Ka * [CH_3COOH] / [CH_3COO^{-}]\\[H_3O^{+}] = 1.8 * 10^{-5} * 0.0826 M / 0.0826 M\\[H_3O^{+}] = 1.8 * 10^{-5} M\\pH = -log[H_3O^{+}]\\pH = -log(1.8 * 10^{-5})\\pH = 4.74[/tex]
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how many ml of 2.11 m hcl are required to react with 2.99 g of calcium? enter only the numeric value for your answer (no units).
By balancing the chemical equation it is deduced that we need 70.8 mL of 2.11 M HCl reacted with 2.99 g of calcium.
To solve this problem, we need to use the balanced chemical equation between calcium (Ca) and hydrochloric acid (HCl):
Ca + 2HCl → CaCl2 + H2
From the equation, we can see that 1 mole of calcium reacts with 2 moles of hydrochloric acid. To determine the number of moles of calcium, we divide the given mass by its molar mass:
2.99 g Ca / 40.08 g/mol = 0.0747 mol Ca
Since 1 mole of Ca reacts with 2 moles of HCl, we need twice as many moles of HCl to react completely with the given amount of Ca:
2 × 0.0747 mol HCl = 0.1494 mol HCl
Finally, we can calculate the volume of 2.11 M HCl solution needed to provide this amount of moles:
The volume of HCl = moles of HCl / Molarity of HCl
Volume of HCl = 0.1494 mol / 2.11 mol/L = 0.0708 L
We convert the volume to milliliters by multiplying by 1000:
0.0708 L × 1000 mL/L = 70.8 mL
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some reactions can be performed without a solvent. what are the benefits of not needing a solvent in a reaction? select one or more: the reaction often costs less because solvents can be expensive. less chemical waste is generated because there are not solvents to remove. reaction progress is easy to monitor because the reagents are more concentrated. the reaction rate is smaller because the concentration of reagents is greater.
Less chemical waste is generated because there are no solvents to remove. The reaction often costs less because solvents can be expensive.
The reaction rate is greater because the concentration of reagents is greater. These options are correct.
A solvent is a substance that dissolves a solute, producing a solution. In addition to being a liquid, a supercritical fluid, a solid, or a gas can also be solvent. All the ions and proteins in a cell are dissolved in water, which is a solvent for polar molecules and the most frequent solvent employed by living things.
chemical reaction, the transformation of one or more chemicals (the reactants) into one or more distinct compounds (the products). Chemical elements or chemical compounds make up substances. In a chemical reaction, the atoms that make up the reactants are rearranged to produce various products.
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what product is formed when the following compound is treated first with lda in thf solution at low temperature, followed by ch3ch2i?
The product formed when the given compound is treated with LDA in THF solution at low temperature followed by CH3CH2I is the corresponding alkene (an elimination product).
The given response includes two stages: first, treatment with LDA (lithium diisopropylamide) in THF (tetrahydrofuran) arrangement at low temperature, and second, response with CH3CH2I. LDA is areas of strength for an and is many times utilized in natural science as a reagent for deprotonation responses. For this situation, it will extract a proton from the carbon neighboring the nitrogen iota, bringing about the development of an enolate middle of the road. This halfway is then gone after by the electrophilic CH3CH2I, prompting the end of a leaving bunch (normally LDA or THF) and the development of the comparing alkene. Generally, this response is an illustration of an end response and is usually utilized in natural combination to shape alkenes from proper beginning materials.
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How do i solve this?
90.0 g of ethene is provided, which is more than the 14.025 g needed to react with 1.5 moles of oxygen in this reaction. There will therefore be some ethene left over once the reaction is finished.
What is the energy of C6H12O6 O2 CO2 H2O?In the process of respiration, six oxygen molecules combine with one glucose molecule to generate six carbon dioxide and water molecules. Equation: C6H12O6 + 6O2 6CO2 + 6H2O + Energy can be used to represent the respiration reaction.
To calculate the amount of ethene required to react with 1.5 moles of O2, we can now utilise stoichiometry:
3 moles of oxygen and 1 mole of ethene react.
1.5 moles of oxygen will react with (1/3) x 1.5 moles of ethene = 0.5 moles of ethene
Then, we can figure out how much 0.5 moles of ethene weigh:
m(ethene) = n(ethene) x Molar mass(ethene)
m(ethene) = 0.5 mol x 28.05 g/mol
m(ethene) = 14.025 g
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explain why molecules with larger mass (molecular weight) move faster in centrifugation but slower in electrophoresis.
In centrifugation and electrophoresis, molecules with larger mass behave differently due to the distinct principles behind these two techniques.
Centrifugation separates molecules based on their size, shape, and mass by applying a strong centrifugal force. Larger molecules with greater mass experience a higher centrifugal force, causing them to move toward the bottom of the tube at a faster rate. This is because the force acting on a molecule is proportional to its masses (Force = Mass × Acceleration). As a result, molecules with larger mass move faster in centrifugation.
On the other hand, electrophoresis separates molecules based on their size, shape, and charge in an electric field. In this technique, molecules move through a porous gel matrix. While smaller molecules can navigate through the pores more easily, larger molecules face greater resistance and move at a slower pace.
Additionally, the speed of a molecule in electrophoresis is also influenced by its charge-to-mass ratio. Molecules with a larger mass and the same charge as smaller molecules have a lower charge-to-mass ratio, making them move slower in the electric field.
In summary, molecules with larger mass move faster in centrifugation due to the greater centrifugal force they experience, while they move slower in electrophoresis because of the increased resistance and lower charge-to-mass ratio they possess.
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at a certain temperature, so2(g) and o2(g) react to produce so3(g) according to the chemical equation shown above. an evacuated rigid vessel is originally filled with so2(g) and o2(g) , each with a partial pressure of 1atm . which of the following is closest to the partial pressure of o2(g) after the system has reached equilibrium, and why? responses 0atm ; because kp is very large, nearly all the so2(g) and o2(g) are consumed before the system reaches equilibrium. 0 atmosphere ; because k sub p is very large, nearly all the s o 2 gas and o 2 gas are consumed before the system reaches equilibrium. 0.5atm ; because kp is very large, nearly all the so2(g) is consumed before the system reaches equilibrium, but an excess amount of o2(g) remains at equilibrium. 0.5 atmosphere ; because k sub p is very large, nearly all the s o 2 gas is consumed before the system reaches equilibrium, but an excess amount of o 2 gas remains at equilibrium. 1atm ; because kp is very large, the system is already near equilibrium, and there will be very little change to the partial pressure of o2(g) . 1 atmosphere ; because k sub p is very large, the system is already near equilibrium, and there will be very little change to the partial pressure of o 2 gas . 1.5atm ; because kp is very large, the decomposition of any so3(g) that forms increases the amount of o2(g) at equilibrium.
The response "0 atm; because kp is very large, nearly all the SO2(g) and O2(g) are consumed before the system reaches equilibrium" is the closest to the correct answer
The balanced chemical equation for the reaction between SO2(g) and O2(g) to produce SO3(g) is:
2SO2(g) + O2(g) ⇌ 2SO3(g)
At a certain temperature, the equilibrium constant for this reaction, Kp, is very large, which indicates that the reaction strongly favors the formation of products (SO3).
In an evacuated rigid vessel initially filled with SO2(g) and O2(g), each with a partial pressure of 1 atm, the reaction will proceed to reach equilibrium. At equilibrium, the partial pressures of SO2(g), O2(g), and SO3(g) will be related by the equilibrium constant Kp as follows:
Kp = (P(SO3))^2 / (P(SO2))^2 x P(O2)
where P(SO2), P(O2), and P(SO3) are the partial pressures of SO2(g), O2(g), and SO3(g) at equilibrium, respectively.
Since Kp is very large, we can assume that the reaction goes to completion and that all of the SO2(g) and O2(g) react to form SO3(g). Therefore, the partial pressure of O2(g) at equilibrium will be zero, and the correct answer is 0 atm.
So the response "0 atm; because kp is very large, nearly all the SO2(g) and O2(g) are consumed before the system reaches equilibrium" is the closest to the correct answer.
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the reaction between leadnitrate and aluminim chloride produces lead chloride and aluminim nitrate. find the mole ratios of lead nitrate to aluminim chloride and lead chloride to aluminum nitrate
The coefficients in the equation indicate that the mole ratio of lead chloride to aluminium nitrate is also 3:2.
The balanced chemical equation for the reaction between lead nitrate (Pb(NO3)2) and aluminium chloride (AlCl3) is:
3Pb(NO3)2 + 2AlCl3 → 3PbCl2 + 2Al(NO3)3
From the balanced equation, we can see that the mole ratio of lead nitrate to aluminium chloride is 3:2.
Similarly, the mole ratio of lead chloride to aluminium nitrate can be determined from the balanced equation. The coefficients in the equation indicate that the mole ratio of lead chloride to aluminium nitrate is also 3:2.
So, the mole ratio of lead nitrate to aluminium chloride is 3:2, which means that for every 3 moles of lead nitrate used in the reaction, 2 moles of aluminium chloride are required.
Likewise, the mole ratio of lead chloride to aluminium nitrate is also 3:2, which means that for every 3 moles of lead chloride produced in the reaction, 2 moles of aluminium nitrate are also produced.
It's worth noting that these mole ratios only apply to the specific reaction between lead nitrate and aluminium chloride, and may be different for other chemical reactions involving these compounds.
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You add a Mg pellet weighing 0.085 g to 7.52 mL of 3 M HCl contained in a foam calorimeter and measure a temperature change of 41.5 oC. What is delta Hrxn in kJ/mol ?
Answer: A 0.86 mol sample of a substance is burned in a bomb calorimeter with a heat capacity of 11.23 kJ/C. The temperature increases by 14.93 C. What is ΔHrxn (in kJ/mol) for the combustion of the substance? Note: please record answer to two decimal places regardless of sig figs
given that the grignard reaction used 1.4555 g phenyl bromide, 10. g carbon dioxide, 0.5734 g magnesium filings, and 30.2 ml of 6m hcl , what was the limiting reagent in the overall reaction, assuming each stepwise reaction ran to completion with only the desired product forming?
The limiting reagent that stops when all the phenyl bromide has been used up, meaning that 0.0079 moles of carbon dioxide will react to produce 0.00395 moles of benzoic acid.
How to find limiting reagent?
The limiting reagent in the overall reaction is phenyl bromide given that the Grignard reaction used 1.4555 g phenyl bromide, 10 g carbon dioxide, 0.5734 g magnesium filings, and 30.2 ml of 6m HCl. This can be determined by calculating the moles of each reactant and identifying which one is limiting in the reaction.
A Grignard reaction is a type of chemical reaction where an alkyl, aryl or vinyl magnesium halide (Grignard reagent) reacts with a carbonyl group, acid halide or ester to produce a tertiary or secondary alcohol, ketone or tertiary or secondary alcohol ester as the product. It is an important reaction for the formation of carbon-carbon bonds.
The balanced equation for the Grignard reaction using phenyl bromide and carbon dioxide is:
2C₆H₅Br + Mg + CO₂ → C₆H₅COOH + MgBr₂
The molar mass of phenyl bromide is 184.01 g/mol.
Therefore, 1.4555 g of phenyl bromide is equal to 0.0079 moles. The molar mass of carbon dioxide is 44.01 g/mol.
Therefore, 10 g of carbon dioxide is equal to 0.227 moles. The molar mass of magnesium filings is 24.31 g/mol.
Therefore, 0.5734 g of magnesium filings is equal to 0.0236 moles.From the balanced equation, it can be seen that 2 moles of phenyl bromide are required to react with 1 mole of carbon dioxide.
Therefore, the number of moles of phenyl bromide needed is twice the number of moles of carbon dioxide.0.227 moles of carbon dioxide is equivalent to 0.454 moles of phenyl bromide. Since only 0.0079 moles of phenyl bromide were used, it is the limiting reagent.
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sample of gas has a volume of 4.25 l at 25.6 oc and 748 mmhg. what will be the volume of this gas at 26.8 oc and 742 mmhg?'
The new volume of the gas at 26.8°C and 742 mmHg is approximately 4.28 L.
To find the new volume of the gas at the given temperature and pressure, we can use the combined gas law formula:
P1 × V1 / T1 = P2 × V2 / T2
where P1 is the initial pressure, V1 is the initial volume, T1 is the initial temperature in Kelvin, P2 is the final pressure, T2 is the final temperature in Kelvin, and V2 is the final volume.
Convert the temperatures to Kelvin.
T1 = 25.6°C + 273.15 = 298.75 K
T2 = 26.8°C + 273.15 = 299.95 K
Convert the pressures to atm.
P1 = 748 mmHg × (1 atm / 760 mmHg) = 0.98421 atm
P2 = 742 mmHg × (1 atm / 760 mmHg) = 0.97632 atm
Rearrange the combined gas law formula to solve for V2.
V2 = P1 × V1 × T2 / (T1 × P2)
Substitute the given values into the formula.
V2 = (0.98421 atm) × (4.25 L) × (299.95 K) / (298.75 K × 0.97632 atm)
Calculate the final volume, V2.
V2 ≈ 4.28 L
The volume of the gas at 26.8°C and 742 mmHg is approximately 4.28 L.
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which of the following statements about the diels-alder reaction are true? true it is a reaction involving pi-electrons. false it is a reaction favored by entropy considerations. false it is a concerted reaction. false it is a [1 3] cycloaddition. false it is a thermal reaction
The statements about diels alder reaction which are true are given in the explanation part.
The following statements about the Diels-Alder reaction are true:
- True: It is a reaction involving pi-electrons.
- True: It is a concerted reaction, meaning that it occurs in a single step without the formation of reaction intermediates.
- False: It is not necessarily favored by entropy considerations, as the reaction can be endothermic and enthalpy-driven.
- True: It is a [4+2] cycloaddition, meaning that it involves the formation of a 6-membered ring from a 4-carbon diene and a 2-carbon dienophile.
- False: While some Diels-Alder reactions can be thermal, others require specific conditions such as high pressure or the use of a catalyst to occur.
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Which of the following is/are true about electrolytes?
Give an example of a solution and identify the solute and solvent.
A common example of a solution is saltwater. In this solution, the solute is salt (NaCl) and the solvent is water (H2O).
When salt is added to water, it dissolves into the liquid to form a homogeneous mixture. The water molecules surround the ions of the salt and pull them apart from each other, resulting in the formation of individual salt ions dispersed throughout the water. The salt ions become evenly distributed throughout the water, resulting in a solution.
In this example, the salt (NaCl) is the solute because it is the substance that is being dissolved. The water (H2O) is the solvent because it is the substance that dissolves the salt and creates the solution.
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what is the lewis acid in the following reaction? nh3 bf3 <---> nh3bf3 group of answer choices bf3 because it receives a lone pair. bf3 because it donates a lone pair. nh3 because it receives a lone pair. nh3 because it donates a lone pair.
The correct answer is option A) BF3 because it receives a lone pair. In this reaction, a Lewis acid-base reaction is taking place, in which a Lewis acid (electron pair acceptor) and a Lewis base (electron pair donor) are reacting to form a coordinate covalent bond.
BF3 serves as an electron pair acceptor and is the Lewis acid. This is due to the fact that BF3 has an open p-orbital that can receive a Lewis base's sole pair of electrons, such as NH3. Here, NH3 serves as an electron pair donor and is a Lewis base.
This is due to the fact that NH3 has a single pair of electrons that can be transferred to the vacant p-orbital in BF3.
This is crucial for forming the coordinating covalent bond that gives rise to the compound NH3BF3 between BF3 and NH3.
Complete Answer:
What is the Lewis acid in the following reaction? NH3 + BF3 <----> NH3BF3
Group of answer choices
A) BF3 because it receives a lone pair
B) BF3 because it donates a lone pair
C) NH3 because it receives a lone pair
D) NH3 because it donates a lone pair
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in the introduction to this experiment, the text states taht small amounts of hcl are present in samples of tert-butyl chloride. write an arrow-pushing mechanism that explains the source of the hcl.
The presence of small of quantity of hydrochloric acid inside the samples of tert-butyl chloride, is attributed to 2 motives: 1. As an impurity in the course of the synthesis of tert-butyl chloride from tert-butyl alcohol and hydrochloric acid. 2. because of the hydrolysis of tert-butyl chloride.
Hydrolysis is a chemical reaction that involves the breaking of a chemical bond in a molecule through the addition of water molecules. This process results in the formation of two or more new molecules. Hydrolysis is an important process in many biological systems, including digestion, where enzymes help break down large molecules such as proteins, carbohydrates, and fats into smaller molecules that can be absorbed and used by the body.
In hydrolysis, water molecules are used to break the bonds between the atoms in the original molecule. One part of the original molecule will gain a hydrogen ion (H+) from the water, while the other part will gain a hydroxide ion (OH-). This process can occur naturally or with the help of enzymes, which are biological catalysts that speed up chemical reactions in living organisms.
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Complete Question:-
In the introduction to this experiment, the text states that small amounts of HCl are present in samples of tert-butyl chloride. Write an arrow-pushing mechanism that explains the source of the HCl.
a 3.02 mol 3.02 mol sample of kr kr has a volume of 417 ml. 417 ml. how many moles of kr kr are in a 5.62 l 5.62 l sample at the same temperature and pressure?
Sample 1 has 0.00724 mol/L of Kr, while sample 2 has 0.0406 mol of Kr.Therefore, the 5.62 L sample contains 0.0406 moles of Kr.
The given data gives the molar grouping of krypton in the underlying example. The molarity can be determined utilizing the equation, Molarity = number of moles of solute/volume of arrangement in liters. Utilizing this recipe, we get the molarity of the underlying example as 7.24 M.
Presently, we can utilize the molarity and volume of the second example to ascertain the quantity of moles of krypton in it utilizing the equation, number of moles of solute = molarity x volume of arrangement in liters. Subbing the given qualities in the recipe, we get the quantity of moles of krypton in the second example as 36.2 mol.Subsequently, there are 36.2 moles of krypton in a 5.62 L example at a similar temperature and strain as the underlying example.
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_____ involves keeping the item for a short amount of time before moving it elsewhere.(1 point)
Responses
Receiving
Holding
Loading
Unloading
Answer:
Holding
Explanation:
keeping the item means to hold the item
Holding. Holding involves keeping the item for a short amount of time before moving it elsewhere.
What distinguishes holding from loading and unloading?While loading and unloading involve the act of adding objects to a truck or container, holding refers to the act of maintaining an item for a brief period of time before transporting it to another location.
What is the use of keeping something before shifting it somewhere else?Retaining something enables for a little interval of time to pass before it is transferred to another location.
What are some instances where holding something before moving it somewhere else is required?When awaiting the arrival of a transport truck, verifying the item for damage, doing quality control checks, or arranging with other employees or departments before the item may be moved, it may be required to hold the item. When the next stage of the process is delayed or the receiving area is not readily accessible, it might also be necessary.
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A ball is dropped from 22m above the ground. Assuming gravity is −9.8ms2, what is its final velocity?
Answer:
We can use the kinematic equation that relates initial velocity, final velocity, acceleration, and displacement:
v^2 = u^2 + 2as
where
u = initial velocity (which is 0 in this case, since the ball is dropped)
v = final velocity (what we're trying to find)
a = acceleration due to gravity (-9.8 m/s^2)
s = displacement (which is the distance the ball falls, or 22 m)
Plugging in the given values, we get:
v^2 = 0 + 2(-9.8)(22)
v^2 = -431.2
Since we can't have a negative final velocity, we need to take the square root of both sides and include a negative sign to indicate that the final velocity is in the opposite direction of the initial velocity:
v = -sqrt(-431.2)
v ≈ -20.8 m/s
So the final velocity of the ball is approximately -20.8 m/s.
Answer:
The final velocity is -20.8 m/s.
Explanation:
To solve this problem, we can use one of the kinematics equations. Let's first write out which variables we know and what we are trying to figure out. (Note that acceleration due to gravity and Δy must have the same sign).
a = -9.8 m/s²
Δy = -22 m
v1 = 0
v2 = ?
Given these variables, we should use the following equation:
v2² = v1² + 2aΔy
Our next step is to substitute in the given variables and simplify.
v2² = (0) + (2)(-9.8 m/s²)(-22m)
v2² = 431.2
Our final step is to take the square root of both sides to find v2.
v2 = √431.2
v2 = -20.8 m/s
Therefore, the final velocity is -20.8 m/s. The velocity must be in the same direction as the displacement and the acceleration, so its sign should be negative.
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effects of influenza
Effects of influenza are A muscle or other part of the body hurts. headaches. fatigue (tiredness) Some people may experience vomiting and diarrhea, which is more prevalent in children than in adults.
What is influenza ?The flu, also known as influenza, is a contagious viral illness that can cause mild to severe symptoms as well as life-threatening complications, including death, in otherwise healthy children and adults.
Influenza viruses primarily move from person to person through coughing or sneezing. They can also be transmitted less frequently by touching a contaminated surface and then touching the mouth, eyes, or nose. Individuals can spread the flu to others even before their own symptoms appear and for up to a week after symptoms appear.
What are diseases caused by influenza ?The influenza virus infects the nose, throat, and sometimes the lungs, causing a contagious respiratory disease. It can bring mild to serious illness and, in extreme cases, death.
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The amount of energy needed to heat 4.3 g of a substance from 50.0°C to 80.0°C is 9.0 J. What is the specific heat capacity of this sample?
Answer:
c = 0.0635 J/g°C
Explanation:
We can use the formula for heat energy:
Q = m * c * ΔT
where Q is the heat energy absorbed by the substance, m is its mass, c is its specific heat capacity, and ΔT is the change in temperature. Rearranging the formula, we get:
c = Q / (m * ΔT)
Plugging in the given values, we get:
c = 9.0 J / (4.3 g * (80.0°C - 50.0°C))
c = 9.0 J / (4.3 g * 30.0°C)
c = 0.0635 J/g°C
Therefore, the specific heat capacity of the substance is 0.0635 J/g°C.
from a ph meter titration curve a student experimentally determines the pka of benzoic acid to be 4.06. calculate the experimental ka for benzoic acid.
From a ph meter titration curve a student experimentally determines the pka of benzoic acid to be 4.06. the experimental ka for benzoic acid is approximately [tex]8.72[/tex] × [tex]10^{-5}[/tex]
To calculate the experimental Ka for benzoic acid, you can use the relationship between Ka and pKa:
pKa = -log(Ka).
In this case, the student determined the pKa to be 4.06.
To find the Ka, you need to use the inverse of the log function, which is [tex]10 ^{-pKa}[/tex].
So, Ka = [tex]10^{-4.06}[/tex]
Ka ≈ [tex]8.72[/tex] × [tex]10^{-5}[/tex]
The experimental Ka for benzoic acid is approximately [tex]8.72[/tex] × [tex]10^{-5}[/tex]
A titration curve is a graph that shows the pH of a solution as a function of the amount of titrant applied.
It is used to calculate the equivalence point, which is the point at which the amount of titrant administered is stoichiometrically equivalent to the amount of analyte in the solution being tested.
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calculate the volume of 1.00 m ammonia and volume of 1.00 m hcl needed to make 50.0 ml of a 0.100 m ammonia buffer with ph
To make 50.0 mL of a 0.100 M ammonia buffer with a pH of 9.25, we need to mix 50.0 mL of 1.00 M ammonia and 50.0 mL of 1.00 M HCl.
To make a buffer solution, we need to mix a weak base and its conjugate acid in the appropriate amounts. In this case, we want to make an ammonia buffer with a pH of approximately 9.25, which is close to the pKa of ammonia (9.25). Henderson-Hasselbalch equation for buffer will be;
pH = pKa + log([A⁻]/[HA])
where [A⁻] is the concentration of the conjugate base (ammonia in this case) and [HA] is the concentration of the weak acid (ammonium ion in this case). We are given that the final buffer solution has a pH of 9.25 and a concentration of 0.100 M.
Calculating the moles of ammonia and ammonium ion needed
pH = pKa + log([A⁻]/[HA])
9.25 = 9.25 + log([A⁻]/[HA])
log([A⁻]/[HA]) = 0
[A⁻]/[HA] = 1
[HA] = [A⁻] = 0.050 M (half the final concentration)
So, we need 0.050 moles of ammonia and 0.050 moles of ammonium ion in the final solution.
Calculating the volume of 1.00 M ammonia needed
0.050 moles = 1.00 M x V
V = 0.050 L = 50.0 mL
So, we need 50.0 mL of 1.00 M ammonia.
Calculating the volume of 1.00 M HCl needed
We can use the equation;
moles of HCl = moles of NH₃ = 0.050
The molarity of HCl can be calculated using the equation;
Molarity = moles of solute/volume of solution (in liters)
0.050 moles / volume = 1.00 M
volume = 0.050 L = 50.0 mL
So, we need 50.0 mL of 1.00 M HCl.
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you need to make a ph 6.5 buffer. which of the following reagents would you choose to make the buffer? explain. pka1, pka2, and pka3 of h3a are 2.44, 6.27, and 9.82, respectively. na3a na2ha nah2a h3a 6. a buffer is made by combining 20.0 ml 0.250 m nh4cl with 30.0 ml 0.250 m nh3. a. calculate the ph of the buffer.
To make a pH 6.5 buffer, we need to choose a weak acid and its conjugate base with a pKa value close to 6.5. Looking at the given pKa values of H3A, we see that pKa2 is the closest to 6.5. Therefore, we should choose the conjugate acid-base pair Na2HA/NaHA.
To prepare the buffer, we would add a solution of Na2HA and NaOH to water and adjust the pH to 6.5 using a pH meter or pH indicator. The resulting solution will be a buffer with a pH of 6.5.
Now, let's move on to the second part of the question:
We are given 20.0 mL of 0.250 M NH4Cl and 30.0 mL of 0.250 M NH3 to prepare a buffer. The relevant equilibrium involved in this buffer is:
NH4+ + NH3 ⇌ NH3 + H+
From the given information, we can find the initial concentrations of NH4+ and NH3 in the buffer solution as:
[NH4+] = (0.250 mol/L) x (20.0 mL/1000 mL) = 0.0050 M
[NH3] = (0.250 mol/L) x (30.0 mL/1000 mL) = 0.0075 M
The equilibrium concentration of NH3 and H+ can be calculated using the Henderson-Hasselbalch equation:
pH = pKa + log([NH3]/[NH4+])
Substituting the given values:
pH = 9.25 + log(0.0075/0.0050) = 9.25 + 0.18 = 9.43
Therefore, the pH of the buffer is approximately 9.43.
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how does gas exchange in a fetus differ from a baby's gas exchange after birth? (2 points) in a fetus, gases diffuse across the alveoli; after birth, gases diffuse across the chorion. in a fetus, gases diffuse through the ductus venosus; after birth, gases diffuse across the alveoli. in a fetus, gases diffuse across the alveoli; after birth, gases diffuse through the ductus venosus. in a fetus, gases diffuse across the chorion; after birth, gases diffuse across the alveoli.
Baby's gas exchange differs from fetus gas exchange because fetus gas exchange propagates through the chorion and after birth, the gases diffuse into the alveoli. Therefore, option (d) is the correct answer here.
Fetal gas exchange: The placenta is responsible for gas exchange between mother and fetus. During pregnancy, it plays the role of the lungs, intestines and kidneys. The placenta has a chorion extension called chorionic villi, which contains small capillaries and is part of the internal organs of the body. These villi are washed in the mother's blood and gas exchange takes place in the placental region. Thus, the gas here diffuses along the chorion.
Gas exchange in babies after birth: During gas exchange, oxygen passes from the lungs to the blood. At the same time, carbon dioxide moves from the blood to the lungs. This happens in the alveoli of the lungs and is due to diffusion.The alveoli are surrounded by blood vessels, so oxygen and carbon dioxide diffuse between the air in the alveoli and the blood in the blood vessels. From the above discussion, we can say that both are differ by each other through option(d).
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Complete question:
how does gas exchange in a fetus differ from a baby's gas exchange after birth? (2 points)
a) in a fetus, gases diffuse across the alveoli; after birth, gases diffuse across the chorion.
b) in a fetus, gases diffuse through the ductus venosus; after birth, gases diffuse across the alveoli.
c) in a fetus, gases diffuse across the alveoli; after birth, gases diffuse through the ductus venosus. d) in a fetus, gases diffuse across the chorion; after birth, gases diffuse across the alveoli.
which of the following yields a buffer solution when equal volumes of the two solutions are mixed? i. 0.10 m hf and 0.10 m naf ii. 0.10 m hf and 0.10 m naoh iii. 0.20 m hf and 0.10 m naoh iv. 0.10 m hcl and 0.20 m naf a. i and ii only b. ii and iv only c. ii and iii only d. i and iv only e. i, iii, and iv only
The correct option is A) i and ii only. Buffer solution is an aqueous solution consisting of a weak acid and its corresponding weak base or vice versa.
The buffer solution can withstand a small amount of acid or base without significant changes in pH. A buffer solution can be made using a weak acid and its corresponding salt, or a weak base and its corresponding salt.
i. 0.10 m HF and 0.10 m NaF solution can yield a buffer solution when equal volumes of the two solutions are mixed.
ii. 0.10 m HF and 0.10 m NaOH solution can also yield a buffer solution when equal volumes of the two solutions are mixed.
iii. 0.20 m HF and 0.10 m NaOH solution cannot yield a buffer solution when equal volumes of the two solutions are mixed. This is because the HF concentration is high in this solution.
iv. 0.10 m HCl and 0.20 m NaF solution cannot yield a buffer solution when equal volumes of the two solutions are mixed. This is because neither HCl nor NaF is a weak acid or weak base.Therefore, the correct option is A) i and ii only.
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For the following question, choose TWO answers. Which question should be asked to determine if the reaction supports the Brønsted- Lowry model of acids and bases?
According to the Brønsted-Lowry model, an acid and its conjugate base differ by a single proton, while a base and its conjugate acid differ by the addition of a single proton. If a reaction produces conjugate acid-base pairs, it supports this model.
To determine if the reaction supports the Brønsted-Lowry model of acids and bases, there are several questions that could be asked. Two possible questions are:
1. Does the reaction involve the transfer of protons (H+ ions) from one molecule to another.This is a key concept in the Brønsted-Lowry model, which defines acids as proton donors and bases as proton acceptors. If a reaction involves the transfer of protons, it supports this model.
2. Do the reactants and products contain conjugate acid-base pairs.
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Answer:
1. Did an acid donate a hydrogen ion to become a conjugate base?
2. Did a base accept a hydrogen ion to become a conjugate acid?
you are using a radioactive isotope to measure the age of a rock in your lab. the half-life of the isotope is 300 million years and the ratio of parent to daughter particles is 1/4. how old is the rock?
To calculate the age of the rock using the radioactive isotope, we can use the formula. Whereas the age of the rock would be approximately 696.579 million years.
t = (t1/2) * log(base 2) (N0/N) Where:
t = age of the rock
t1/2 = half-life of the isotope
N0 = initial number of parent particles
N = current number of parent particles
Given that the half-life of the isotope is 300 million years, we can substitute t1/2 = 300 million years into the formula.
Also, the ratio of parent to daughter particles is 1/4, which means that for every 1 parent particle, there are 4 daughter particles. This also means that the total number of particles (parent + daughter) is 5.
Let's assume that we started with N0 parent particles. Then, the number of daughter particles would be 4N0. Therefore, the total number of particles N would be N0 + 4N0 = 5N0.
Since the ratio of parent to daughter particles is currently 1/4, the current number of parent particles is 1/5 of the total number of particles, which is (1/5)*N.
Substituting all these values into the formula, we get:
t = (300 million years) * log(base 2) (N0 / (1/5)*N0)
Simplifying the expression inside the logarithm, we get:
t = (300 million years) * log(base 2) 5
Using a calculator, we can evaluate log(base 2) 5 to be approximately 2.32193.
Substituting this value into the formula, we get:
t = (300 million years) * 2.32193
t = 696.579 million years
Therefore, the age of the rock is approximately 696.579 million years.
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the gas pressure inside a container decreases when group of answer choices the temperature is increased. the number of gas molecules is decreased. the number of gas molecules is increased. the number of molecules is increased and the temperature is increased. previousnext
The gas pressure inside a container decreases when the temperature is increased. Option A is correct.
Increasing the temperature of a gas decreases its pressure due to increased average kinetic energy of the gas molecules, leading to more collisions with the container walls. When the temperature of a container rises, the gas pressure within falls. This is known as Charles's Law, which states that at a constant volume, the pressure of a gas is directly proportional to its temperature. When the temperature of a gas increases, the gas molecules gain kinetic energy and move faster, colliding more frequently with the container walls.
This increases the force of the gas molecules on the container walls, which in turn increases the gas pressure. Conversely, when the temperature decreases, the gas molecules move slower and collide less frequently with the container walls, leading to a decrease in gas pressure.
The number of gas molecules does not directly affect the gas pressure inside a container, as pressure is a function of temperature, volume, and the number of moles of gas present. However, increasing the number of gas molecules will increase the pressure if the temperature and volume are held constant. Option A is correct.
The complete question is
The gas pressure inside a container decreases when
Group of answer choices
A. The temperature is increased.
B. The number of gas molecules is decreased.
C. The number of gas molecules is increased.
D. The number of molecules is increased and the temperature is increased.
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lactic acid, hc3h5o3, has one acidic hydrogen. a 0.10m solution of lactic acid has a ph of 2.44. calculate ka
Given: The concentration of lactic acid: [C₃H₆O₃] = 0.1 M
The pH value of the solution: pH = 2.44
To calculate: Kₐ for lactic acid
The concentration of hydronium ions can be calculated by using the pH value.
[H₃O⁺] = 10⁻[tex]^{pH}[/tex]
= 10[tex]^{-2.44}[/tex]
= 0.00363 M
The ICE table for the dissociation of lactic acid is given:
Initial (M): C₃H₆O₃ + H₂O ⇄ C₃H₅O₃⁻ + H₃O⁺
Change (M): -x +x +x
Equilibrium (M): 0.1M - x x 0.00363 M
From the ICE table at the equilibrium condition
x = [H₃O⁺] = [C₃H₅O₃⁻] = 0.00363 M
[C₃H₅O₃⁻] = 0.1 M - x
= 0.1 M - 0.00363 M
0.09637 M
The expression for Kₐ = [H₃O⁺] [C₃H₅O₃⁻] / [C₃H₆O₃]
On substituting the corresponding values in the equation,
Kₐ = 0.00363 M × 0.00363 M / 0.09637 M
= 1.37 × 10⁻⁴
Hence the Kₐ for lactic acid is 1.37 × 10⁻⁴.
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an acid ha has a ka value of 4.40 x 10-4. 25.0 ml of 0.100 m ha is titrated with 0.25 m naoh. after the equivalence point is reached, 3 ml of 0.25 m naoh are added. what is the ph of the solution at this point?
At the equivalence point and after the addition of 3 mL of 0.25 M NaOH, the pH of the solution is approximately 4.36.
The first step in solving this problem is to determine the moles of acid (HA) present in the initial solution.
moles of HA = concentration of HA x volume of HA
moles of HA = 0.100 M x 0.0250 L
moles of HA = 0.00250 mol
Next, we need to determine the amount of NaOH needed to reach the equivalence point. Since we have a 1:1 stoichiometric ratio between HA and NaOH, the moles of NaOH required to reach the equivalence point will be equal to the moles of HA present.
moles of NaOH = 0.00250 mol
To calculate the volume of NaOH required to reach the equivalence point, we can use the equation;
moles of NaOH =concentration of NaOH x volume of NaOH
0.00250 mol = 0.25 M x volume of NaOH
volume of NaOH = 0.0100 L = 10.0 mL
This means that 10.0 mL of 0.25 M NaOH will be required to reach the equivalence point.
At the equivalence point, all of the HA has reacted with the NaOH to form the salt, sodium salt (NaA), and water. This means that the moles of NaOH added to reach the equivalence point will be equal to the moles of HA that have reacted;
moles of NaOH = 0.0100 L x 0.25 M = 0.00250 mol
moles of HA reacted = 0.00250 mol
The total volume of the solution at the equivalence point is:
volume of solution = volume of HA + volume of NaOH
volume of solution = 0.0250 L + 0.0100 L
volume of solution = 0.0350 L
The concentration of the resulting solution after the addition of 10 mL of 0.25 M NaOH is;
moles of NaOH added = 0.0100 L x 0.25 M = 0.00250 mol
moles of NaA formed = 0.00250 mol
moles of HA remaining = moles of HA - moles of HA reacted = 0.00250 mol
concentration of NaA = moles of NaA / volume of solution = 0.00250 mol / 0.0350 L = 0.0714 M
concentration of HA = moles of HA / volume of solution = 0.00250 mol / 0.0350 L = 0.0714 M
Since NaA is the conjugate base of the weak acid HA, the solution is a buffer. To calculate the pH of the buffer solution, we can use the Henderson-Hasselbalch equation;
pH = pKa + log([A⁻]/[HA])
where pKa is the acid dissociation constant of HA, [A⁻] is the concentration of the conjugate base (NaA), and [HA] is the concentration of the weak acid (HA).
The pKa of HA is given as 4.40 x 10⁻⁴, so we can substitute this value along with the concentrations of NaA and HA to get:
pH = -log(4.40 x 10⁻⁴) + log(0.0714/0.0714)
pH = 4.36
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