ENTHALPHY LAB QUESTIONS!!


PURPOSE OF EXPERIMENT: To find Heat of Solution of sodium hydroxide and to find the heat of neutralization between sodium hydroxide and hydrochloric acid.


Experiment 1 Procedure:

1. Measure 50.0 mL of water (tap) into a 100 mL graduated cylinder and pour it into a large coffee cup.

2. Determine the temperature of this water

3. Measure out 2.00 g of sodium hydroxide into a piece of paper towel *tare scale!

4. Add the sodium hydroxide to the water in the coffee cup and put a small cup over it, with the thermometer through the hole. Stir GENTLY with the thermometer and record the temperature every 30 seconds for 3 minutes or until it peaks. Record this in a properly labelled table.

5. Let this stand for 45 minutes before proceeding to Exp. 2.


WHAT WE FOUND IN EXP 1:

T (temp.) initial = 20 degrees C

T (temp) FINAL = 28.5 degrees C

moles of sodium hydroxide = 0.0518mol

the molar mass of sodium hydroxide = 39.969g/mol

C (specific heat of water) = 4.184J/g degrees C


THE NUMBER OF TRIALS FOR TEMP IN EXP 1

1st trial = 21 C

2nd trial = 24.5 C

3rd trial = 26 C

4th trial = 26 C

5th trial = 28 C

6th trial = 28.5 C

7th trial = 28.5 C (final temp)


ANALYSIS FOR EXPERIMENT ONE:

1. Determine the moles of sodium hydroxide (NaOH) from the experiment.

2. Determine Qsurroundings and Qrxn

3. Determine the enthalpy for the dissociation of sodium hydroxide (delta H sol)

4. Write the thermochemical equation for the dissociation of sodium hydroxide TWO ways and write an enthalpy diagram

5. What assumptions did you make to calculate #2? (some example assumptions to make: assume that the solution is water and that heat and density COULD be the same as water, etc)

6. Research the actual value and determine the percent error

7. In terms of bonds breaking and forming, what is RESPONSIBLE FOR ENTHALPY CHANGE?


EXPERIMENT 2 PROCEDURE:

1. Measure out 50.0 mL of 0.75 concentration M HCl into a graduated cylinder

2. Measure and record the temperature of the sodium hydroxide solution from exp. 1.

3. Add the hydrochloric acid solution to the sodium hydroxide solution, put the small cup on, and record the temperature change every 15 seconds for 1 minute. Stir GENTLY. Record this in a properly labelled table (will be given below)

4. Solutions can be discarded down the sink.


WHAT WE FOUND IN EXP. 2:

T (temp) initial = 23.5 C

T (temp) FINAL = 27 C


THE NUMBER OF TRIALS FOR TEMP IN EXP 2

1st trial = 27 C

2nd trial = 27 C

3rd trial = 27 C

4th trial = 27 C (FINAL TEMP)


ANALYSIS FOR EXPERIMENT 2:

1. Determine the moles of HCl added to this mixture

2. Write the chemical equation for this reaction

3. Determine the limiting reagent

4. Determine the Qsurr and Qrxn *CONVERT TO kJ*

5. Determine the enthalpy for the neutralization reaction.

6. Write the thermochemical equation for the dissociation of sodium hydroxide TWO WAYS and write an enthalpy diagram

7. Research the actual value and determine the percent error.

8 Explain sources of experimental error for both experiments and BE SPECIFIC! (NOT CALCULATION ERRORS, SPILLING, OR LOSING REACTANTS - DO NOT COUNT AS ERRORS! They can be EXPERIMENTAL due to heat loss/gain, room temp *specific heat capacity is for 25 C*, and atmospheric pressure is constant. And they can be MEASUREMENTS - consider the precision and the potential range of error for each measurement)

9. In terms of bonds breaking and forming, what's responsible for the enthalpy change?


CONCLUSION: write a brief statement that refers to the purpose.

Answers

Answer 1

In Experiment 1, we found the heat of solution of sodium hydroxide (NaOH) by dissolving 2.00 g of NaOH in 50.0 mL of water.

What was observed in the experiment?

The temperature rose from 20°C to 28.5°C. The moles of NaOH were determined to be 0.0518 mol.

Using the specific heat of water (4.184 J/g°C), we calculated the enthalpy change (ΔH_sol) and compared it to the literature value, finding a percent error.

In Experiment 2, we measured the heat of neutralization between NaOH and 0.75 M HCl.

The temperature increased from 23.5°C to 27°C. We determined the moles of HCl, limiting reagent, and enthalpy change (ΔH_neut) for the neutralization reaction.

The actual value was compared to the literature value, and percent error was calculated.

Experimental errors in both experiments could arise from heat loss/gain, variations in room temperature and atmospheric pressure, and imprecise measurements.

The enthalpy changes in both experiments are due to bond breaking and forming during the dissociation of NaOH and the neutralization reaction between NaOH and HCl.

In conclusion, we determined the heat of solution for sodium hydroxide and the heat of neutralization between sodium hydroxide and hydrochloric acid, and analyzed the possible sources of experimental errors.


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Related Questions

Standard vinegar solutions are about 5% acetic acid by mass. What is the molarity of a 5% vinegar solution? The molar mass of acetic acid is 60.052 g/mol. The density of the solution is 1.01 g/mL.

Answers

Explanation:

To calculate the molarity of the vinegar solution, we first need to calculate the number of moles of acetic acid present in one liter of the solution.

Since the density of the solution is 1.01 g/mL, one liter of the solution will have a mass of 1.01 kg.

The mass of acetic acid in one liter of the solution can be calculated as follows:

mass of acetic acid = 5% × 1.01 kg = 0.0505 kg

The number of moles of acetic acid can be calculated using its molar mass:

moles of acetic acid = mass of acetic acid / molar mass of acetic acid

moles of acetic acid = 0.0505 kg / 60.052 g/mol

moles of acetic acid = 0.000841 mol

Therefore, the molarity of the vinegar solution is:

molarity = moles of acetic acid / volume of solution in liters

molarity = 0.000841 mol / 1 L

molarity = 0.000841 M

So, the molarity of a 5% vinegar solution is approximately 0.000841 M.

Original Claims: In general, what types of substances tend to be acidic?

Fruit Juices
Beverages (Coffee/Soda/Milk)
Cleaning Products
Digestive Juices
Answer in this format.

Restate original Claim here. This claim was ______ (supported/ not supported) by the claim because ________.(give a brief description of the correct claim using terms pH, COLOR and pH PAPER)

For example, from the evidence,_____ (use THREE specific examples from your evidence of the pH value and color of the pH paper to support your answer)

Answers

Restate original Claim here. This claim was supported by the claim because the evidence showed that acidic substances have a pH value less than 7 and cause the pH paper to turn a certain color.

What is pH?

pH is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm of the concentration of hydrogen ions (H+) in a solution. pH values range from 0 to 14, where 0 is the most acidic, 7 is neutral, and 14 is the most basic. A change of one unit in pH represents a tenfold change in the concentration of hydrogen ions.

For example, from the evidence, fruit juices such as lemon juice have a pH value of around 2-3 and turn the pH paper a red color, which indicates acidity. Beverages such as coffee and soda also have a low pH value, around 4-5, and turn the pH paper a slightly red color. Cleaning products such as vinegar have a pH value of around 2-3 and turn the pH paper a red color as well.

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I need help with these questions. If you help me i will mark you as most brainiest :) Thank you, have a great day!

Answers

Al, Cu, and Zn, Al are the metals in equations 1 and 2, respectively. Since aluminium is ranked higher on the activity series than copper, it can substitute for copper in chemical reactions.

Which metal in the experiment using metals and water reacts violently and ignites?

Metal and Water Reaction: An Introduction Because of the intense interactions that certain metals have with water, such potassium and sodium, they will ignite if left outside.

Which metal reacts slowly when exposed to cold water yet swiftly when exposed to steam?

Magnesium is therefore the most reactive of the listed metals, and as a result, its pace of reaction will be the quickest (to react with steam). Magnesium does not react with cold water, whereas metals with strong reactivity like potassium (K), sodium (Na), and calcium (Ca) do.

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forgot how to solve this​

Answers

The value of the equilibrium constant, Kc is 0.33.

The correct option is A.

What is the value of the equilibrium constant, Kc?

The balanced chemical equation for the oxidation of NO by O2 is:

2 NO (g) + O2 (g) → 2 NO2 (g)

From the stoichiometry of the equation, we see that the mole ratio of NO to O2 consumed is 2:1. Therefore, if 3 moles of O2 are present at equilibrium, then 1.5 moles of NO have been consumed:

1.5 moles NO = 15.0 moles NO (initial) - 3.0 moles NO2 - 3.0 moles O2

Using the law of mass action, we can express the equilibrium constant (Kc) for the reaction as:

Ke = ([NO2]^2 / [NO]^2 [O2])

We know that at equilibrium, [O2] = 3.0 moles / 1.0 L = 3.0 M. To calculate [NO2], we need to use the stoichiometry of the equation and the fact that 1.5 moles of NO are consumed at equilibrium:

2 mol NO → 2 mol NO2

1.5 mol NO → 1.5 mol NO2

Therefore, [NO2] = 1.5 mol NO2 / 1.0 L = 1.5 M. Substituting the values into the equilibrium constant expression, we get:

Ke = ([NO2]^2 / [NO]^2 [O2])

Ke = (1.5 M)^2 / (1.5 M)^2 (3.0 M)

Ke = 0.333

Therefore, the answer is (a) 0.33.

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Order the following elements from most to least reactive.
sodium, carbon, krýpton
sodium, krypton, carbon
krypton, sodium, carbon
carbon, sodium, krypton

Answers

It is the least reactive of the three elements listed.  The correct order of elements from most to least reactive is:

sodium, carbon, krypton.

Sodium is a highly reactive metal and readily forms compounds with many other elements. It reacts vigorously with water and air, which is why it is stored in oil to prevent contact with moisture or oxygen.

Carbon is less reactive than sodium but can still undergo reactions, such as combustion or oxidation. Krypton, on the other hand, is a noble gas and is chemically inert, meaning it does not react with other elements under normal conditions. Therefore, it is the least reactive of the three elements listed.

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if you start with 2.196 g of salivic acid what is the theoretical yield of aspirin​

Answers

To determine the theoretical yield of aspirin, we need to know the balanced chemical equation for the reaction between salicylic acid and acetic anhydride, which produces aspirin and acetic acid. The balanced chemical equation is:

C7H6O3 + C4H6O3 → C9H8O4 + C2H4O2

From the balanced equation, we can see that the molar ratio between salicylic acid and aspirin is 1:1. Therefore, if we know the amount of salicylic acid used, we can determine the theoretical yield of aspirin.

The molar mass of salicylic acid is 138.12 g/mol and the molar mass of aspirin is 180.16 g/mol. Therefore, the number of moles of salicylic acid present in 2.196 g can be calculated as:

2.196 g / 138.12 g/mol = 0.0159 mol

Since the molar ratio of salicylic acid to aspirin is 1:1, the theoretical yield of aspirin would be 0.0159 mol.

The mass of this amount of aspirin can be calculated as:

0.0159 mol x 180.16 g/mol = 2.86 g

Therefore, the theoretical yield of aspirin is 2.86 g.

Plants capture the sun's energy and make food in the process of photosynthesis. Only about 0.1 percent of the sun's energy is captured by plants. Plants take carbon dioxide and water and, using the energy from sunlight, convert it into glucose (food) and oxygen. About one-half of the energy absorbed by plants is used right away. The other half is stored in plants as energy-containing food (carbohydrates).

A green maple leaf with the chemical equation of photosynthesis below it, its reactants above and to the left and its products to the right of it.
A green maple leaf with the chemical equation of photosynthesis below it. The chemical equation has reactants of coefficient 6, CO subscript 2, +, coefficient 6, H subscript 2, 0, a yields arrow with the label light above it and chlorophyll below it, and products of coefficient 6 C subscript 6, H subscript 12, 0 subscript 6, + coefficient 6 0 subscript 2. Above the leaf is a down arrow pointing to the center of the left. To the left of this arrow is a rain cloud labeled water and to the right is a beaming sun labeled light. To the left of the lead is a grey cloud of gas labeled carbon dioxide with an arrow pointing toward the leaf. To the right of the lead are two parallel arrows the top of which points to the label glucose and the bottom to the label oxygen.

2. How do you think energy from the sun ends up in the crust, tomato sauce, cheese, and meat on a slice of pizza?

Answers

The food chain that produces elements like the crust, tomato sauce, cheese, and meat on a pizza begins with the energy that plants absorb from the sun through photosynthesis.

What is photosynthesis?

Green plants, algae, and some microorganisms transform solar energy into chemical energy in the form of organic compounds like carbohydrates through a process called photosynthesis. Light energy is absorbed by pigments, chiefly chlorophyll, which is present in the chloroplasts of plant cells, during photosynthesis. Next, using this energy, glucose (a form of sugar) and oxygen are produced from carbon dioxide and water.

By photosynthesis, plants use the sun's energy to create carbohydrates (like glucose). Following the consumption of these carbohydrates by herbivores, predators subsequently consume these carbs, and so on.

When it comes to a pizza, the wheat used to form the crust was probably grown in a field where it employed photosynthesis to take in energy from the sun. Like with other vegetables used as toppings, the tomatoes used to prepare the sauce were probably also grown in a field. Pizza's cheese is formed from milk, which comes from cows who eat grass and other plants that have undergone photosynthesis to receive solar energy. Last but not least, any meat added as a garnish originated from creatures that also ate vegetables for fuel.

In a sense, the sun's energy, which plants use to produce food, including the components in a pizza, is eventually harnessed by photosynthesis.

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what is the current produced y 120 volts passing through a resistance of 0.2 ohms?

Answers

Ohm’s Law states:

V= I • R

where V is voltage (volts)
where I is current (amps)
and R is resistance (ohms)

Rearrange the equation to solve for current:

I = V/R

Now plug in what you know:

I = (120 volts)/(0.2 ohms)

Solve for I:

I = 600 amps

Hope this helps!

How many moles of gas are in a 34.2 L container at 1 atm of pressure and 273.15 K?

Answers

Answer:

1.525834 (1.53 when accounting for significant figures).

Explanation:

This problem relies on the Ideal Gas Law, PV = nRT, where P is pressure, V is volume, n is moles, R is a specific constant, and T is temperature. In this problem, we are solving for n, moles, so we would rewrite it as n = PV/RT. Since the units here are moles, liters, atmospheres, and kelvin, R would be the value in atmosphere liter per mole kelvin, or 0.0821. From here, you just enter the values in the fraction and calculate.

For the significant figures, I followed the measurement of 34.2 L, giving 3, although an argument could be made for 1 significant figure from 1 atm, I imagine your professor would want something more specific than 2.

Calculate the volume of oxygen produced in the decomposition of 5 moles of KCIO3 at STP?​

Answers

The volume of oxygen produced in the decomposition of 5 moles of KCIO3 at STP is 168 L. The balanced chemical equation for the decomposition of KCIO3 is:

2KClO3(s) → 2KCl(s) + 3O2(g)

From the equation, we can see that for every 2 moles of KCIO3, 3 moles of O2 are produced. Therefore, for 5 moles of KCIO3, the number of moles of O2 produced can be calculated as follows:

5 moles KCIO3 x (3 moles O2/2 moles KCIO3) = 7.5 moles O2

Since the conditions are given as STP (standard temperature and pressure), we can use the molar volume of a gas at STP (22.4 L/mol) to calculate the volume of O2 produced:

7.5 moles O2 x 22.4 L/mol = 168 L O2

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Need help with this please and thank you. PBS poisoned water student questions

Answers

When exposed to lead at high levels, the brain and central nervous system are attacked, resulting in unconsciousness, convulsions, and even death.

Future generations could be impacted by lead poisoning.

Lead poisoning affects up to 800 million children worldwide, or close to one third of all children. Lead has a negative impact on a child's developing brain, leading to diminished IQ, behavioral difficulties, and learning issues that can lower potential earnings as an adult.

How much lead is permitted by law in US drinking water?

The Safe Drinking Water Act (SDWA) reduced the maximum permitted lead level, or "lead-free" content, to a weighted average of 0.25 percent measured throughout the wetted surfaces of pipes, pipe fittings, plumbing fixtures, and fixtures, and 0.2 percent for solder and flux.

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What are the toxic effects of lead? How can it affect the human body?

A certain first-order reaction ( A→products
) has a rate constant of 8.70×10−3 s−1
at 45 ∘C
. How many minutes does it take for the concentration of the reactant, [A]
, to drop to 6.25 %
of the original concentration?

Answers

Answer:

time = 1.92 min

Explanation:

By knowing that

[tex]R_R = K_R [A]^{1} = \frac{[A]}{time}[/tex]  

Where: RR: rate of forward reaction, KR: rate constant, [A]: A concentration

in the previous equation, [A] is cancelled, then:

[tex]K_R = \frac{1}{time} \\ \\[/tex]


[tex]8.70\times10^{-3} = \frac{1}{time}[/tex]


Then, time = 114.94 seconds = 1.92 minutes


hope you find this easy to understand....

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using the balanced chemical reaction equations, and the energies of the reactants and products, calculate the combustion of glucose O2 = 498kj/1 mol o2, 1598kj/1mol H2O = 934kj/1mol H2O, use correct units

Answers

One mole of glucose burns to produce several gases. [tex]6600kJ[/tex] of power. Another way to put it is that the burning of glucose releases  [tex]6600KJ/mol[/tex]  thermal energy.

What's a straightforward explanation of combustion?

A chemical reaction between two or more substances, typically containing oxygen, is called combustion. It results in the production of light and heat in the form of a flame.

The correct chemical formula for the burning of glucose

[tex]C6H12O6 + 6O2 \rightarrow  6CO2 + 6H2O[/tex]

We can determine the change in enthalpy for this reaction by using the values provided for the enthalpies of formation of the reactants and products:

Reactants:

[tex]C_6H_1_2O_6[/tex] : not given

[tex]O2: -498 kJ/mol \times 6 = -2988 kJ/mol[/tex]

Products:

[tex]CO_2[/tex]: not given

[tex]H2O -1598 kJ/mol \times 6 = -9588 kJ/mol[/tex]

[tex]\Delta H = (\epsilon products) - (\epsilon reactants)[/tex]

[tex]\Delta H = (-9588 kJ/mol + 0) - (0 + -2988 kJ/mol)[/tex]

[tex]\Delta H = -6600 kJ/mol[/tex]

Therefore, One mole of glucose burns to produce several gases. [tex]6600kJ[/tex] of power. Another way to put it is that the burning of glucose releases  [tex]6600KJ/mol[/tex]  thermal energy.

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What is the normality of the solution that results when 4.0g of Al(NO3)3 (MW = 213.0) is dissolved in enough water to give
250mL of solution? What is the molarity of the solution?

Answers

the normality of the solution that results when 4.0g of Al(NO₃)₃ (MW = 213.0) is dissolved in enough water to give 250mL of solution the molarity of the solution is 0.0751 M.

To calculate the normality and molarity of the solution, we need to know the number of moles of Al(NO₃)₃ in the solution.

The number of moles can be calculated as:

moles = mass / molar mass

where mass is the mass of Al(NO₃)₃ and molar mass is the molecular weight of Al(NO₃)₃

Substituting the given values, we get:

moles = 4.0 g / 213.0 g/mol = 0.01878 mol

The volume of the solution is given as 250 mL, which is equivalent to 0.25 L.

The normality of the solution is defined as the number of equivalents of solute per liter of solution. For Al(NO₃)₃, each mole of the compound produces 3 moles of ions, so the number of equivalents of Al(NO₃)₃ is:

equivalents = moles x 3

Substituting the value of moles, we get:

equivalents = 0.01878 mol x 3 = 0.05634 eq

The normality can now be calculated as:

normality = equivalents / volume

Substituting the given values, we get:

normality = 0.05634 eq / 0.25 L = 0.225 N

Therefore, the normality of the solution is 0.225 N.

The molarity of the solution is defined as the number of moles of solute per liter of solution. The number of moles of Al(NO₃)₃ in 250 mL of solution is the same as the number of moles in 1 L of solution, which is 0.01878 mol. Therefore, the molarity of the solution is:

molarity = moles / volume

Substituting the given values, we get:

molarity = 0.01878 mol / 0.25 L = 0.0751 M

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Give the IUPAC name for: image attached ​

Answers

The IUPAC name of the given compound is 1-bromo-3-ethylpentane.

What are the steps involved in writing IUPAC name?

IUPAC (International Union of Pure and Applied Chemistry) naming is a system used to give standardized names to chemical compounds. The steps involved in doing IUPAC naming are as follows:

1. Identify the longest carbon chain: The parent chain is the longest continuous chain of carbon atoms in the molecule.

2. Number the carbon atoms: The carbon atoms in the parent chain are numbered starting from the end nearest to the substituent, and the substituents are given numbers based on the carbon to which they are attached.

3. Identify and name the substituents: Substituents are groups of atoms that replace hydrogen atoms on the parent chain. They are named according to their functional groups.

4. Write the name: The name of the compound is written by listing the names of the substituents in alphabetical order, along with their position on the parent chain.

5. Add prefixes and suffixes: Prefixes are added to indicate the number of substituents on the parent chain, and suffixes are added to indicate the functional group present.

6. Check the name: The final step is to check the name for accuracy and consistency with IUPAC rules.

It's important to note that the naming of complex organic compounds can involve additional rules and naming conventions beyond these basic steps.

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you take a 25g chalk piece outside and draw for 5 min the chalk weighs 5g after how many molecules of chalk did you leave outside on the concreate. the chalk is CaCO3.

Answers

AnswerTherefore, you left approximately 1.202 x 10^23 molecules of CaCO3 on the concrete after drawing with a 25g chalk piece outside for 5 minutes.

Explanation:

To solve this problem, we need to use the concept of conservation of mass, which states that matter cannot be created or destroyed, only transformed from one form to another. Therefore, the total mass of the chalk before and after drawing must be equal.

The mass of the chalk before drawing is 25 g. After drawing for 5 minutes, the mass of the chalk is 5 g. Therefore, the mass of chalk that was used for drawing is:

25 g - 5 g = 20 g

Next, we need to convert the mass of the chalk used to the number of molecules. The molar mass of CaCO3 is 100.09 g/mol, which means that one mole of CaCO3 contains 6.022 x 10^23 molecules.

To calculate the number of molecules of chalk used for drawing, we can use the following steps:

Calculate the number of moles of CaCO3 used:

20 g / 100.09 g/mol = 0.1998 mol

Calculate the number of molecules of CaCO3 used:

0.1998 mol x 6.022 x 10^23 molecules/mol = 1.202 x 10^23 molecules

An unknown element contains 11 protons, 11 neutrons and 12 electrons, which of the following options do you think the unknown element is?

Answers

Answer:Sodium

Explanation:Sodium has 11 protons, 11 nuetrons, and 12 electrons

sample gas has a pressure of 6.8 kPa at 539K. If the temperature decreases to 211K, then what will be the new pressure?

Answers

Gay-Lussac's Law-

[tex] \:\:\:\:\:\:\star\longrightarrow \underline{\sf \boxed{\sf \dfrac{P_1}{T_1}=\dfrac{P_2}{T_2}}}[/tex]

[tex] \:\:\:\:\:\:\star\longrightarrow \sf \underline{P_2=\dfrac{P_1 \:T_2}{T_1}}[/tex]

Where-

P₁ is the initial pressure.T₁ is the initial temperatureP₂ is the final pressure.T₂ is the final temperature  

As per question, we are given -

P₁ = 6.8 KPaT₁ =539 KT₂= 211K

Now that we are given all the required values, so we can put them into the formula and solve for P₂:-

[tex] \:\:\:\:\:\:\:\:\:\:\:\:\longrightarrow \sf P_2=\dfrac{P_1 \:T_2}{T_1}\\[/tex]

[tex] \:\:\:\:\:\:\:\:\:\:\:\:\longrightarrow \sf P_2=\dfrac{6.8\times 211}{539}\\[/tex]

[tex]\:\:\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf P_2 = \dfrac{1434.8}{539}\\[/tex]

[tex] \:\:\:\:\:\:\:\:\:\:\:\:\longrightarrow \sf P_2 = 2.661966.........\\[/tex]

[tex]\:\:\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf\underline{ P_2 = 2.7 \:KPa}\\[/tex]

Therefore, If the temperature decreases to 211K, then the new pressure will become 2.7 KPa.

How many milliliters (mL) of a 0.310 M NaOH solution are needed to neutralize 10.0 mL of 0.115 M H2SO4

Answers

10.0 mL of 0.115 M [tex]H_2SO_4[/tex] needs to be neutralised with 0.370 mL of a 0.310 M NaOH solution.

Calculate how much 0.310 M NaOH is required to neutralise 10.0 mL of 0.115 M [tex]H_2SO_4[/tex] in millilitres, we can apply the following formula:

Moles of [tex]H_2SO_4[/tex] = (Concentration of [tex]H_2SO_4[/tex])(Volume of [tex]H_2SO_4[/tex])

Moles of [tex]H_2SO_4[/tex] = (0.115 M)(10.0 mL) = 0.00115 moles

Since the reaction is 1 mole of [tex]H_2SO_4[/tex] to 2 moles of NaOH, we must have 0.00115 moles of NaOH to neutralize the [tex]H_2SO_4[/tex].

Moles of NaOH = (Concentration of NaOH)(Volume of NaOH)

0.00115 moles = (0.310 M)(Volume of NaOH)

Volume of NaOH =[tex]\frac{ 0.00115 moles}{0.310 M } = 0.370 mL[/tex]

Therefore, 0.370 mL of a 0.310 M NaOH solution are needed to neutralize 10.0 mL of 0.115 M [tex]H_2SO_4[/tex].

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Consider the reaction. 2Pb(s)+O2(g)⟶2PbO(s) An excess of oxygen reacts with 451.4 g of lead, forming 338.4 g of lead(II) oxide. Calculate the percent yield of the reaction.

Answers

The reaction's per cent yield is  69.5%.

Calculation-

We must compare the actual yield of the reaction to the theoretical yield of the reaction to get the per cent yield of the reaction.

First, we need to calculate the amount of Pb reacted using the given mass of Pb:

mass of Pb = 451.4 g

The molar mass of Pb is 207.2 g/mol, so the number of moles of Pb reacted is:

moles of Pb = mass of Pb / molar mass of Pb

moles of Pb = 451.4 g / 207.2 g/mol

moles of Pb = 2.179 mol

The theoretical yield of PbO can be calculated using the molar mass of PbO:

mass of PbO = moles of PbO × molar mass of PbO

mass of PbO = 2.179 mol × 223.2 g/mol

mass of PbO = 486.6 g

Therefore, the theoretical yield of PbO is 486.6 g.

The per cent yield of the reaction is:

per cent yield = (actual yield / theoretical yield) × 100%

per cent yield = (338.4 g / 486.6 g) × 100%

percent yield = 69.5%

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CAN SOMEONE HELP WITH THIS QUESTION?✨

Answers

The molarity of the sodium hydroxide solution is 0.0911 M.

We must figure out how many molecules of potassium hydrogen phthalate there are.

moles of KHP = mass / molar mass = 0.600 g / 204.22 g/mol = 0.00294 mol

We know that 0.00294 moles of NaOH were used in the titration because one mole of KHP interacts with one mole of NaOH. This data can be used to determine the molarity of the NaOH solution:

molarity of NaOH = moles of NaOH / volume of NaOH used in liters

volume of NaOH = 32.21 mL = 0.03221 L

calculation of  the molarity of NaOH:

molarity of NaOH = 0.00294 mol / 0.03221 L = 0.0911 M

The molarity of the sodium hydroxide solution is 0.0911 M.

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WORTH 50 POINTS, ANSWER ALL PARTS

For each of the following gemstones, determine the mass of compound present in the given moles of each compound.

PART A. The chemical formula for ruby is Al₂O₃. What is the mass in grams of ruby that are in 0.0924 moles?
PART B. The chemical formula for emerald is Be₃Al₂(SiO₃)₆. What is the mass in grams of emerald that are in 0.0165 moles?
PART C. The chemical formula for garnet is MgAl₂(SiO₄)₃. What is the mass in grams of garnet that are in 0.0380 moles?

Answers

Answer:

0.0924 mol Al₂O₃ = 9.42 g

0.0165 mol Be₃Al₂(SiO₃)₆ = 8.87 g

0.0380 mol MgAl₂(SiO₄)₃ = 13.5 g

Explanation:

mass = number of moles * molar mass

(PART A) The molar mass of Al₂O₃ is 101.96 g/mol. To find the mass in grams of Al₂O₃ that are in 0.0924 moles:

0.0924 mol * 101.96 g/mol = 9.42 g

(PART B) The molar mass of Be₃Al₂(SiO₃)₆ is 537.51 g/mol. To calculate the mass in grams of 0.0165 moles of Be₃Al₂(SiO₃)₆:

0.0165 mol * 537.51 g/mol = 8.87 g

(PART C) The molar mass of MgAl₂(SiO₄)₃ is 354.52 g/mol. To calculate the mass in grams of 0.0380 moles of MgAl₂(SiO₄)₃:

0.0380 mol * 354.52 g/mol = 13.5 g

The mass of ruby in grams is 9.43 g.
The mass of emerald in grams is 8.87 g.
The mass of garnet in grams is 16.56 g.


To calculate the mass of a compound in grams, we need to know the molar mass of the compound, which is the sum of the atomic masses of all the atoms in the formula. Once we know the molar mass, we can use the formula:

mass in grams = number of moles x molar mass

where the number of moles is given and the molar mass is calculated from the formula. In each case, we plug in the numbers and perform the calculation to obtain the mass in grams.


PART A: molar mass of Al₂O₃ is 101.96 g/mol (2 x 26.98 g/mol for Al and 3 x 16.00 g/mol for O).

As a result, the ruby mass in grammes is:

0.0924 moles x 101.96 g/mol = 9.43 g

PART B: The molar mass of Be₃Al₂(SiO₃)₆ is 537.54 g/mol (3 x 9.01 g/mol for Be, 2 x 26.98 g/mol for Al, 6 x 28.09 g/mol for SiO₃).

Therefore, The mass of an emerald in gram is :

0.0165 moles x 537.54 g/mol = 8.87 g

PART C: The molar mass of MgAl₂(SiO₄)₃ is 435.52 g/mol (1 x 24.31 g/mol for Mg, 2 x 26.98 g/mol for Al, 3 x 60.08 g/mol for SiO₄).

Therefore, the garnet mass in grams is :

0.0380 moles x 435.52 g/mol = 16.56 g

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What volume will 1.02 mol of carbon monoxide gas occupy at STP?

Answers

1.02 mol of carbon monoxide gas will occupy a volume of approximately 22.8 liters at STP.

At STP (standard temperature and pressure), the temperature is 273.15 K (0°C) and the pressure is 1 atmosphere (atm). The molar volume of a gas at STP is 22.4 L/mol.

Using the ideal gas law, we can calculate the volume of 1.02 mol of carbon monoxide gas at STP: PV = nRT

where:

P = pressure = 1 atm

V = volume (unknown)

n = moles = 1.02 mol

R = gas constant = 0.0821 L·atm/(mol·K)

T = temperature = 273.15 K

V = (nRT)/P

putting the values,

V = (1.02 mol)(0.0821 L·atm/(mol·K))(273.15 K) / (1 atm)

V = 22.4 L/mol

V = 22.8 L

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What is the base conjugate acid pair in this balanced equation NH3+HNO3→NH4+ + NO3-

Answers

Answer:

The base conjugate acid pair is NH3 and NH4+.

NH3/NH4+

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Enthalpy Lab + Questions NEED HELP ASAP FOR THE ANALYSIS QUESTIONS (be sure to show your work) + CONCLUSION

PURPOSE OF EXPERIMENT: To find Heat of Solution of sodium hydroxide and to find the heat of neutralization between sodium hydroxide and hydrochloric acid.

Experiment 1 Procedure:
1. Measure 50.0 mL of water (tap) into a 100 mL graduated cylinder and pour it into a large coffee cup.
2. Determine the temperature of this water
3. Measure out 2.00 g of sodium hydroxide into a piece of paper towel *tare scale!
4. Add the sodium hydroxide to the water in the coffee cup and put a small cup over it, with the thermometer through the hole. Stir GENTLY with the thermometer and record the temperature every 30 seconds for 3 minutes or until it peaks. Record this in a properly labelled table.
5. Let this stand for 45 minutes before proceeding to Exp. 2.

WHAT WE FOUND IN EXP 1:
T (temp.) initial = 20 degrees C
T (temp) FINAL = 28.5 degrees C
moles of sodium hydroxide = 0.0518mol
the molar mass of sodium hydroxide = 39.969g/mol
C (specific heat of water) = 4.184J/g degrees C

THE NUMBER OF TRIALS FOR TEMP IN EXP 1
1st trial = 21 C
2nd trial = 24.5 C
3rd trial = 26 C
4th trial = 26 C
5th trial = 28 C
6th trial = 28.5 C
7th trial = 28.5 C (final temp)

ANALYSIS FOR EXPERIMENT ONE:
1. Determine the moles of sodium hydroxide (NaOH) from the experiment.
2. Determine Qsurroundings and Qrxn
3. Determine the enthalpy for the dissociation of sodium hydroxide (delta H sol)
4. Write the thermochemical equation for the dissociation of sodium hydroxide TWO ways and write an enthalpy diagram
5. What assumptions did you make to calculate #2? (some example assumptions to make: assume that the solution is water and that heat and density COULD be the same as water, etc)
6. Research the actual value and determine the percent error
7. In terms of bonds breaking and forming, what is RESPONSIBLE FOR ENTHALPY CHANGE?

EXPERIMENT 2 PROCEDURE:
1. Measure out 50.0 mL of 0.75 concentration M HCl into a graduated cylinder
2. Measure and record the temperature of the sodium hydroxide solution from exp. 1.
3. Add the hydrochloric acid solution to the sodium hydroxide solution, put the small cup on, and record the temperature change every 15 seconds for 1 minute. Stir GENTLY. Record this in a properly labelled table (will be given below)
4. Solutions can be discarded down the sink.

WHAT WE FOUND IN EXP. 2:
T (temp) initial = 23.5 C
T (temp) FINAL = 27 C

THE NUMBER OF TRIALS FOR TEMP IN EXP 2
1st trial = 27 C
2nd trial = 27 C
3rd trial = 27 C
4th trial = 27 C (FINAL TEMP)

ANALYSIS FOR EXPERIMENT 2:
1. Determine the moles of HCl added to this mixture
2. Write the chemical equation for this reaction
3. Determine the limiting reagent
4. Determine the Qsurr and Qrxn *CONVERT TO kJ*
5. Determine the enthalpy for the neutralization reaction.
6. Write the thermochemical equation for the dissociation of sodium hydroxide TWO WAYS and write an enthalpy diagram
7. Research the actual value and determine the percent error.
8 Explain sources of experimental error for both experiments and BE SPECIFIC! (NOT CALCULATION ERRORS, SPILLING, OR LOSING REACTANTS - DO NOT COUNT AS ERRORS! They can be EXPERIMENTAL due to heat loss/gain, room temp *specific heat capacity is for 25 C*, and atmospheric pressure is constant. And they can be MEASUREMENTS - consider the precision and the potential range of error for each measurement)
9. In terms of bonds breaking and forming, what's responsible for the enthalpy change?

CONCLUSION: write a brief statement that refers to the purpose.

Answers

The difference between the energy needed to break the bonds in the reactants and the energy released when new bonds are created in the products is what essentially determines the enthalpy change.

What impact does bond breaking have on enthalpy?

In general, a bond must be broken by a positive change in enthalpy, whereas a bond must be formed by a negative change in enthalpy. In other words, the process of breaking a bond is endothermic, whereas the process of forming a bond is exothermic.

What is the bond-breaking and bond-forming reaction's enthalpy change?

The energy needed to break the links between the reactants less the energy released during the formation of new bonds in the products is the enthalpy of reaction.

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In terms of bonds breaking and forming, what's responsible for the enthalpy change?

help please been asking for days LOLLL keep getting the wrong answers.

Answers

Answer:

22.24°C.

Explanation:

The change in temperature of the iron can be calculated using the formula: ΔT = Q / (m * c), where ΔT is the change in temperature, Q is the heat added, m is the mass of the substance and c is the specific heat capacity.

Substituting the given values into the formula: ΔT = 115 cal / (47.0 g * 0.11 cal/g⋅°C) ≈ 22.24°C

So, the change in temperature of the iron is 22.24°C.

Discuss two pre-requisite skills needed for students to learn the process of writing balanced chemical and ionic equations​

Answers

Answer:

Explanation:Two pre-requisite skills needed for students to learn the process of writing balanced chemical and ionic equations are:

1. Understanding of the periodic table and elements: Students must have a solid foundation in the periodic table, including recognizing elements by their symbols and understanding their properties, groups, and electron configurations.

2. Knowledge of chemical bonding and compound formation: Students should be familiar with the different types of chemical bonds (ionic, covalent, and metallic) and know how to construct chemical formulas for compounds based on their component elements and valence electrons.

12. 50cm³ of alcohol is mixed with 50cm³ of water. The volume of the mixture is 97cm³. Which o the following is the best explanation for this observation red?​

Answers

The alcohol and water molecules sharing the same space leads to a more compact arrangement of the molecules in the combination, which is the best explanation for the observed drop in volume.

When alcohol and water are combined, what happens to the volume?

In this illustration, adding water to alcohol results in a final volume that is roughly 10% lower than the combined volumes of the two liquids. The "vanishing volume" results from variations in how the solvent molecules are packed in the mixture compared to the pure components.

Why does the volume drop when alcohol and water are combined?

Alcohol molecules slide into the spaces between the water molecules as it dissolves, reducing the volume.

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If 50cm³ of alcohol is mixed with 50cm³ of water. The volume of the mixture is 97cm³. What is the best explanation for this observation?

A. Water evaporates leading to decrease in volume of the mixture

B. Water and alcohol molecules react and form a compact solution

C. Alcohol being volatile evaporates and decreases the volume of the mixture

D. The alcohol and water molecules sharing the same space leads to the decrease in volume of the mixture

Which term describes the energy the reactant molecules must meet for a reaction to progress?
O average kinetic energy of reactants
O enthalpy
O activation energy
O average kinetic energy of products

Answers

Answer:

Activation Energy

Explanation:

Activation energy is the minimum amount of energy that reactant molecules must possess in order to undergo a chemical reaction. as it is necessary to break the bonds of between the molecules of the reactants.


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Activation Energy !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Label each change as gradual or rapid:
Hurricane = ________
Volcanic eruption = ________
Regrowth after volcanic eruption = ________
Flooding = ________
Seasonal changes = ________
Oceans increasing temperature = ________
Global warming = ________
Fire = ________

Answers

Hurricane = Rapid

Volcanic eruption = Rapid

Regrowth after volcanic eruption = Gradual

Flooding = Rapid

Seasonal changes = Gradual

Oceans increasing temperature = Gradual

Global warming = Gradual

Fire = Rapid

Answer:

rapid

rapid

gradual

rapid

gradual

gradual

gradual

rapid

Explanation:

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