A buffer solution is one in which the pH of the solution is "resistant" to small additions of either a strong acid or strong base. Buffers usually consist of a weak acid and its conjugate base, in relatively equal and "large" quantities. Calculations are based on the equation for the ionization of the weak acid in water forming the hydronium ion and the conjugate base of the acid. "HA" represents any weak acid and "A-" represents the conjugate base.
HA(aq) + H2O(l) --> H3O+(aq) + A-(aq)
Ka = [H3O+][A-]
Consider the following chemical reaction:
4 Al(s) + 3 O2(g) ⟶2 Al2O3(s)
If 4.2 grams of Al reacts with 3.0 grams of O2,
1. How many grams of Al2O3 could be produced?
2. Which reactant is limiting?
3. Which reactant is excess?
4. How much of the excess reactant would remain?
Answer:
1. mAl₂O₃ = 6.42 g
2. O₂
3. Al.
4. mAl = 1.67 g
Explanation:
Let's calculate the moles of Al and O2 first before doing any other calculations. The molecular weights of Al and O are 26.98 g/mol and 16 g/mol, so the moles are:
moles = mass / Atomic weight or molar mass
moles Al = 4.2 / 26.98 = 0.156 moles
moles O2 = 3 / (2*16) = 0.094 moles
The molar mass of Al2O3 is:
MM = (2 * 26.98) + (3*16) = 101.96 g/mol
With these data, let's determine each part:
1, 2 and 3. Grams of Al2O3, limiting and excess reactant:
To do this, we need to know which is the limiting reactant. this reactant will tell us how many moles are produced of Al2O3 and then, with the previously calculated molar mass, we can determine its mass. Let's see again the overall reaction taking place:
4Al + 3O₂ ---------> 2Al₂O₃
According to this reaction, 4 moles of Al reacts with 3 moles of oxygen, so:
If: 4 moles Al ---------> 3 moles O₂
Then: 0.156 moles ----------> X
X = 0.156 * 3/4 = 0.117 moles of O₂ required.
However, we do not have 0.117 moles of O₂, we have 0.094 moles, therefore we can conclude that the oxygen is the limiting reactant and Aluminum is the excess reactant.
Now, the moles produced of Al₂O₃ will be:
3 moles O₂ -------> 2 moles Al₂O₃
0.094 moles -------> Y
Y = 0.094 * 2/3 = 0.063 moles of Al₂O₃
Finally the mass would be:
mAl₂O₃ = 0.063 * 101.96
mAl₂O₃ = 6.42 g4. mass of excess reactant:
The mass of excess reactant would be:
moles Al = 0.156 - 0.094 = 0.062 moles
mAl = 0.062 * 26.98
mAl = 1.67 gHope this helps
4. The formation of an ionic bond involves the
a. transfer of electrons.
b. transfer of neutrons.
c.
transfer of protons.
d. sharing of electrons.
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The formation of Ionic bond involves Transfer of electrons.
Correct answer is A.) transfer of electrons
_____________________________
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A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place
over the next few minutes?
Molecules in both the metal and the surrounding air will start moving at lower speeds.
Molecules in both the metal and the surrounding air will start moving at higher speeds.
The air molecules that are surrounding the metal will slow down, and the molecules in the metal will speed up.
The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.
Answer:
Molecules in both the metal and the surrounding air will start moving at higher speeds.
Explanation:
Temperature is defined as a measure of the average kinetic energy of the molecules of a body.
The greater the temperature of a body, the greater the average kinetic energy of the molecules of the body and the greater the speed of the particles of the body.
A metal at 150°C will witness an increase in the average kinetic energy of its molecules, the molecules will speed up as temperature increases.
Similarly, the hot metal plate releases heat to the surrounding air molecules by radiation causing the surrounding air molecules to experience an increase in temperature and average kinetic energy. Thus the air molecules surrounding the metal hot plate also speed up.
10. Which of the following is an example of a
chemical change?
A. burning a scented candle
B. cutting an apple into slices
C. freezing liquid water into an ice cube
D. melting a stick of butter to pour over popcorn
Select the correct answer. Which is true according to the law of conservation of energy? A. In a closed system, the total amount of energy in the universe keeps on changing. B. The supply of energy is limited, so it is essential to conserve it. C. In a closed system, energy can be created and destroyed. D. In a closed system, energy cannot be used faster than it is created. E. In a closed system, the total energy always remains constant.
in the image there is answer okk
The moon phase takes about a year to complete.....True or false?
Answer:
the answer is false and the reason why is because every 29 days it completes one full cycle
Explanation:
What type of reaction is shown below c10H8+12O2 10co2+4H2O
Answer:
Explanation:
Combustion. Have fun with that.
Pasagot kailangan Asap
Answer:mmhm
Explanation:
mhhm
Answer:
do u want the answer now?
Which statement is true about the electric field?
Question 3 options:
The field points away from positive charges and toward negative charges.
The strength of the field increases proportional to the charge that creates it.
The strength of the field decreases proportional to the square of the distance from the charge.
All of the above
Pick the selection that increases in energy.
7f, 6s, 4p
4s, 4p, 4d
1s, 6f, 4d
3d, 4s, 3p
Answer:
i think mix im um 1s 6f 4d is correct answer
What is atomic radius?
Answer:
The atomic radius of a chemical element is the measure of the size of its atoms, usually the mean or typical distance from the centre of the nucleus to the boundary of surrounding shells of electrons
Hope it helps :)
Aşağıdakilerden hangisi ülkemizde nesli tüken-
me tehlikesi taşıdığı için koruma altına alınan
canlılardan birisidir?
A) Koyun
B) At
Kardelen çiçeği (bitkisi)
D) Panda
Answer:
D seçeneği doğru
Explanation:
Türkiye'de kırmızı pandalar tehlike altında. Pandaların neslinin tükenmesinin ana nedenleri:
a) Habitat tahribatı
b) Genetik varyasyon kaybı, dolayısıyla onları hayatta kalmak için daha az uygun hale getirir
Bu nedenle, D seçeneği doğrudur
Give two different conditions under which long chain hydrocarbons may be cracked.
Answer:
Various methods can be used for cracking, eg catalytic cracking and steam cracking: Catalytic cracking uses a temperature of approximately 550°C and a catalyst known as a zeolite which contains aluminium oxide and silicon oxide. Steam cracking uses a higher temperature of over 800°C and no catalyst.
To make a solution for an experiment, Gunther needs to add 40 g of a solute to 100 g of water. When making the solution at room temperature, he could only add 34 grams before the solute settled out.
What could he do to dissolve the remaining 6 grams of the solute?
Answer:
B. Heat the solution, dissolve the solute, and let the solution cool verifying nothing settled out.
Explanation:
To dissolve more solute, the solution has been heated at a high temperature, and the cooling has been observed to verify proper dissolution.
The solubility of the compound has been the ability of the solvent to dissolve the solute molecules. For the solution formation, the intermolecular forces between the solute molecules have been broken in order to sustain the interaction between the solute and the solvent molecules,
The interaction between solute and solvent molecules results in the dissolution of the solute in the solvent.
When Gunther dissolves the 34 grams, of solute, the energy of the solvent molecules has been enough to break the solute interactions and dissolve the solute molecules.
However, in order to dissolve more molecules, the solvent molecules are provided with the energy that has been able to increase the kinetic energy of the solvent for the dissolution of more solute.
The kinetic energy of the solvent has been increased with the increase in the temperature, thereby adding to the more dissolution of the solute.
Thus, to dissolve more solute in the solvent, the solution has been heated at a high temperature, and the cooling has been observed to verify the absence of precipitate thereby proper dissolution.
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Calculate the mass percent composition of nitrogen in each nitrogen containing compound
Mass percent of a compound=(mass of element in molecule/total mass of compound)×100 (a) 63.64%
What is mass percentage composition ?We use the concept of mass percentage composition to explain the concentration of an element in a compound or a component in a combination. This word refers to the overall percent by mass of each element present in a compound.
In chemistry, a compound's percent composition is calculated by dividing its total amount of each elements by the compound's total amount, multiplied by 100. The following formula determines an element's percentage composition:
(gE/gT) = %CE 100
Here, %CE stands for the element's composition in percent.
How to calculate the percentage of each element by mass makes up each compound?
To get the mass percent of an element in a compound, multiply the result by 100 after dividing the mass of the element in 1 mole of the compound by the compound's molar mass.
Calculating total mass of HNO3
= 1 x 1 + 14 x 1 + 16 x 3
= 1 + 14 + 48
= 63
Calculating the mass percentage of Nitrogen in HNO3
= 1/63 x 100
= 1.586 %
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structure of potassium trioxalatoaluminate(iii)?
Answer:
K3[Al(C2O4)3] is the answer
What is a solution?
Two solutes mixed together
A solute and solvent mixed together
A solute or solvent by themselves
Two solvents mixed together
oc
d
Answer:
A solute and a solvent mixed together.
Explanation:
A solution is a solute and a solvent mixed together. An example would be salt water. Salt would be the solute (the thing that's getting dissolved) and water would be the solvent (the thing that does the dissolving)
During the electrolysis of molten sodium chloride, which ion discharges at the anode?
Answer:
it should be chlorine gas
Explanation:
How does a fire help grasslands? Choose all that apply
Question 5 options:
keeps trees from overtaking the grasses
preserve biodiversity
helps contain only coarse grass
all of the above
Answer:
I believe its all above
Explanation:
Fire on grasslands keep the tress from overtaking the grasses on fire. They can thereby preserve biodiversity. Fire on grassland helps contains coarse grass only. Therefore, all of the above is correct.
What are the impacts of fire on grasslands?The addition of nutrients to the soil, the facilitation of easier grazing by herd animals, and the inhibition of the establishment of invasive plant species all contribute to the health and sustainability of grasslands.
The grassland ecology benefits from the natural occurrence of fire since it keeps it strong and healthy. It increases the soil's temperature and lessens the annual buildup of leaf litter, allowing sunshine to enter.
Warming the soil stimulates microbial activity, which liberates nutrients from decomposing plant matter that are essential for the growth of new grasses and flowers. All the given points are in direct or indirect way help the grassland.
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If 0.034 moles of potassium nitrate were formed how many moles of lead (II) nitrate did you start
with?
Answer:
0.017 mole of Pb(NO₃)₂.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2KOH + Pb(NO₃)₂ —> 2KNO₃ + Pb(OH)₂
From the balanced equation above,
1 mole of Pb(NO₃)₂ reacted to produce 2 moles of KNO₃.
Finally, we shall determine the number of mole of Pb(NO₃)₂ required to produce 0.034 mole of KNO₃. This can be obtained as follow:
From the balanced equation above,
1 mole of Pb(NO₃)₂ reacted to produce 2 moles of KNO₃.
Therefore, Xmol of Pb(NO₃)₂ will react to produce 0.034 mole of KNO₃ i.e
Xmol of Pb(NO₃)₂ = 0.034 / 2
Xmol of Pb(NO₃)₂ = 0.017 mole.
Thus, 0.017 mole of Pb(NO₃)₂ is needed for the reaction.
Use the ideal gas law to find the volume that 4.30 mol of oxygen gas occupies at 99.7 kPa and 35.0 °C.
help please
According to the ideal gas law, 4.30 molecule of o2 occupies 0.11 m³ at 99.7 kPa with 35.0 °C.
What is a straightforward definition of ideal gas law?The relationship between a gas's pressure P, volumes V, and t in the range between low pressures and extremely high temperatures, when the gas's water moves virtually independently of one another, is known as the ideal gas, also known as the perfect gas law.
PV = nRTp = pressure in PaV
= volume in m³n = number of molesR
= molar gas constant (8.31 JK⁻¹mol⁻¹)T
= temperature in Kpressure ⇒ 99.7 × 10³ Pa
temperature ⇒ 35.0 + 273 = 308
KpV = nRT
= 99.7×10³×V= 4.30×8.31×308V
=(4.30×8.31×308)/(99.7×10³3 )V
= 0.11 m³
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Why do some elements not take part in chemical bonds?
Answer:
Because there is some element which is already in an octet state and has no need to achieve it, they have a full electron in their outermost shells such as helium, argon etc.
ammonia chemically reacts with oxygen gas to produce nitric oxide and water. what mass of oxygen gas is consumed by the reaction of 8.4 g of ammonia?
the mass of nitric oxide produced by the reaction of 8.4 g of oxygen gas is 4.32 g. ammonia chemically reacts with oxygen gas to produce nitric oxide and water.
What oxygen is used for?Common uses of oxygen include production of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.
Why is oxygen important?Oxygen helps organisms grow, reproduce, and turn food into energy. Humans get the oxygen they need by breathing through their nose and mouth into their lungs. Oxygen gives our cells the ability to break down food in order to get the energy we need to survive.
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Help!!!
1.
Q: How does the distillation apparatus remove impurities from water?
Q: Why does water vapour condense in the condenser tube?
Q: As the boiling animation neared the end, what does the change in the proportion of particle types in the boiling flask indicate about the impurities?
Answer:
Q1) Distillation relies on evaporation to purify water
Explanation:
contaminated water is heated to form steam. inorganic compounds and large non-volatile organic molecules do not evaporate with the water and are left behind. The steam then cools and condenses to form purified water
A 2.5 L container is filled with propane. The ambient temperature is 25°C and the
pressure in the container is about 3 atmospheres. If the temperature in the car
reaches 55°C (about 130°F), what will be the pressure in the container?
Answer:
The pressure inside the container will be 3.3 atmospheres
Explanation:
The relationship between the temperature and pressure of a gas occupying a fixed volume is given by Gay-Lussac's law which states that the pressure of a given amount of gas is directly proportional to its temperature on the kelvin scale when the volume is kept constant.
Mathematically, it expressed as: P₁/T₁ = P₂/T₂
where P₁ is initial pressure, T₁ is initial temperature, P₂ is final pressure, T₂ is final temperature.
The above expression shows that the ratio of the pressure and temperature is always constant.
In the given question, the gas in the can attains the temperature of its environment.
P₁ = 3 atm,
T₁ = 25 °C = (273.15 + 25) K = 298.15 K,
P₂ = ?
T₂ = (55 °C = 273.15 + 55) K = 328.15 K
Substituting the values in the equation
3/298.15 = P₂/328.15
P₂ = 3 × 328.15/298.15
P₂ = 3.3 atm
Therefore, the pressure inside the container will be 3.3 atmospheres
Which statement is correct about the rate of a chemical reaction? (5 points)
a. It increases when the concentration of reactants increases.
b. It does not depend on the concentration of reactants.
c. It increases when the temperature decreases.
: d. It does not depend on the temperature.
Answer:
they don't depend on the temperature
if 3.38g of CuNO3 IS DISSOLVED IN WATER TO MAKE 0.220 M solution what is the volume of the solution in milliliters"
Answer:
To determine the volume of the solution in milliliters, we need to know the mass of CuNO3 and the concentration of the solution.
Given that 3.38g of CuNO3 is dissolved in water to make a 0.220 M solution, we can use the following formula to calculate the volume of the solution:
Volume = (Mass of CuNO3) / (Concentration of solution)
Plugging in the given values, we have:
Volume = (3.38 g) / (0.220 M)
Converting the mass to grams and the concentration to moles/liter, we have:
Volume = (3.38 g) / (0.220 mol/L)
Calculating, we find that the volume of the solution is approximately 15.36 liters.
To convert the volume to milliliters, we can multiply the volume in liters by 1000. In this case, the volume in milliliters is 15,360 ml.
Therefore, the volume of the solution in milliliters is approximately 15,360 ml.
Explanation:
What is the calculated value of the cell potential at 298K for an electrochemical cell with the following reaction, when the Hg2 concentration is 7.36E-4 M and the Al3 concentration is 1.05 M
Answer:
Explanation:
Concentration of Hg⁺² = 7.36 x 10⁻⁴ M
Concentration of Al⁺³ = 1.05 M
2Al + 3Hg⁺² = 2Al⁺³ + 3Hg .
E = E₀ + RT / nF ln [ Al⁺³]² / [ Hg⁺² ]³
E₀ = reduction potential of Hg⁺² minus reduction potential of Al⁺³
= 0.92 V - ( - 1.66 V )
= 2.58 V
E = 2.58 + .059 /n log [ Al⁺³]² / [ Hg⁺² ]³
n = 6 , [Al⁺³] = 1.05 M ; [Hg⁺²] = 7.36 x 10⁻⁴ M
E = 2.58 + .059 /6 log [ 1.05]² / [ 7.36 x 10⁻⁴ ]³
= 2.58 + .059 /6 log 27.65 x 10⁸ .
= 2.58 + .059 /6 [8+ log 27.65 ].
= 2.58 + .059 /6 [8+ log 27.65 ].
= 2.58 + .09
= 2.67 V .
what mass of O2(g) is required to completely react with 25.0g of Fe(s)?
3Fe(s) + 2O2(g) → Fe3O4(s) (Balanced)
Plz help me well mark brainliest if Correct!!...
Answer:
C
Explanation:
Answer:
C
Explanation:
The specific place where an organism lives is called its habitat.