Question 1

If the theoretical yield for a reaction is 72.3 g, and 65.2 g of product are actually obtained, what is the percent yield?

Accepted Answer

A) 90.2% 
B) 0.902% 
C) 7.10% 
D) 111% 
E) not enough information given

Question 2

Iron metal reacts with chlorine gas according to the following equation: 2Fe(s)+ 3Cl2(g)→ 2FeCl3(s)If 25.6 g each of iron and chlorine are combined, how much FeCl3 should form?

Accepted Answer

A) 74.3 g 
B) 113 g 
C) 39.0 g 
D) 49.5 g 
E) 26.0 g

Question 3

Which of the following is an exothermic process?

Accepted Answer

A) ice melting 
B) water evaporating 
C) boiling soup 
D) condensation of water vapor 
E) Ammonium thiocyanate and barium hydroxide are mixed, resulting in a decrease in temperature

Question 4

The burning of a 2.50 g sample of pizza in a bomb calorimeter gives off 2.53 x 104 J of energy. If the calorimeter contains 2440 g of water, what was the temperature change of the water? [C_water = 4.184 J/(g°C)] Report your answer with the correct number of significant figures.

Accepted Answer

The answer of The burning of a 2.50 g sample...

Question 5

In photosynthesis, plants convert carbon dioxide and water into glucose, C₆H₁₂O₆, according to the reaction: 6CO₂(g)+ 6H₂O(l)→ 6O₂(g)+ C₆H₁₂O₆(g)How many grams of glucose can be synthesized from 117 g of CO₂, assuming there is sufficient water to react with all of the CO₂? Report your answer with the correct number of significant figures and correct units.

Accepted Answer

The answer of In photosynthesis, plants convert carbon dioxide and...

Question 6

When mixed, solutions of copper(II)nitrate, Cu(NO3)2, and sodium phosphate, Na3PO4, will form a precipitate of copper phosphate, Cu3(PO4)2. The balanced equation is 3Cu(NO3)2(aq)+ 2Na3PO4(aq)→ Cu3(PO4)2(s)+ 6NaNO3(aq)Which of the following statements regarding this reaction is incorrect?

Accepted Answer

A) 8 moles of Na3PO4 will react with 12 moles of Cu(NO3)2. 
B) 1 mole of NaNO3 should form when 0.5 mole of Cu(NO3)2 reacts with sufficient Na3PO4. 
C) 12 moles of Cu3(PO4)2 should form when 36 moles of Cu(NO3)2 reacts with sufficient Na3PO4. 
D) If 10 moles of Na3PO4 react with sufficient Cu(NO3)2, 4 moles of Cu3(PO4)2 should form. 
E) If 5 moles of Cu3(PO4)2 are needed, it would require the combination of 15 moles of Cu(NO3)2 and 10 moles of Na3PO4.

Question 7

When potassium metal is exposed to air, it forms a coating of potassium oxide, according to the following equation: 4K(s)+ O₂(g)→ 2K₂O(s)If a piece of potassium gains 0.354 g, assuming this gain can be attributed to the above reaction with oxygen, what mass of potassium reacted? Report your answer with the correct number of significant figures and correct units.

Accepted Answer

The answer of When potassium metal is exposed to air,...

Question 8

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: ___P4(s)+ ___Cl2(g)→ ___PCl3(l)(unbalanced)Balance the equation and determine how many grams of chlorine would be required to react with 10.6 g of phosphorus.

Accepted Answer

A) 6.07 g 
B) 24.3 g 
C) 36.4 g 
D) 18.5 g 
E) 74.1 g

Question 9

Phosphorus trichloride can be made by the following reaction: P4(s)+ 6Cl2(g)→ 4PCl3(l)What is the maximum amount of phosphorus trichloride that can be formed if 10 molecules of P4 are mixed with 36 molecules of chlorine?

Accepted Answer

A) 4 molecules 
B) 6 molecules 
C) 12 molecules 
D) 24 molecules 
E) 46 molecules

Question 10

When mercury(II)oxide, a red crystalline solid, is heated, it decomposes to form liquid mercury and oxygen gas, according to the following equation: ___HgO(s)→ ___Hg(l)+ ___O2(g)(unbalanced)Balance the equation and determine the mass of mercury that should be formed when 12.3 g of HgO is heated.

Accepted Answer

A) 22.8 g 
B) 11.4 g 
C) 5.70 g 
D) 13.3 g 
E) 6.64 g

Question 11

The coefficients of a balanced equation can be understood to represent either relative numbers of moles or relative mass.

Accepted Answer

A) True 
 B)False

Question 12

When 5.0 g CaCl2 is dissolved in enough water to make a 0.500 L solution, what is the molarity of ions in solution?

Accepted Answer

A) 0.135 M 
B) 0.045 M 
C) 0.270 M 
D) 10.0 M 
E) 2.50 M

Question 13

When one molecule of propane, C3H8, burns in a gas grill, it combines with five oxygen molecules to form three CO2 molecules and four H2O molecules. Select the statement below that is incorrect in regard to this reaction.

Accepted Answer

A) The balanced equation for the reaction is C3H8 + 5O2 → 3CO2 + 4H2O. 
B) If 5 propane molecules react, 15 CO2 molecules should form. 
C) If 5 propane molecules react, 25 O2 molecules must also react. 
D) If 15 O2 molecules react, 9 H2O molecules should form. 
E) If 12 CO2 molecules are formed, then 4 propane molecules must have reacted.

Question 14

Consider the following reaction: CrCl3(s)+ KCl(s)+ 2H2SO4(l)→ KCr(SO4)2(s)+ 4HCl(g)green white colorless purple colorless solid solid liquid solid gas When the green solid is mixed with the white solid and the colorless liquid is added, the mixture starts to bubble and fume. When all action has stopped, a wet purple solid containing solid white specks remains. Which substance is the limiting reactant?

Accepted Answer

A) CrCl3 
B) KCl 
C) H2SO4 
D) KCr(SO4)2 
E) HCl

Question 15

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the following equation: ___P4(s)+ ___Cl2(g)→ ___PCl3(l)(unbalanced)Balance the equation and determine how many grams of phosphorus reactant would be required to produce 75.0 g of phosphorus trichloride, assuming there is sufficient chlorine available.

Accepted Answer

A) 67.8 g 
B) 135 g 
C) 16.9 g 
D) 271 g 
E) 333 g

Question 16

Given the balanced equation 4NH3(g)+ 5O2(g)→ 4NO(g)+ 6H2O(g), if 82.0 g of NH3 react with sufficient oxygen, how many grams of NO should form?

Accepted Answer

A) 145 g 
B) 5.80 x 102 g 
C) 46.5 g 
D) 186 g 
E) 11.6 g

Question 17

If the theoretical yield for a reaction is 54.9 g, and 51.3 g of product are actually obtained, the percent yield is

Accepted Answer

A) 0.934%. 
B) 93.4%. 
C) 107%. 
D) 3.60%. 
E) not enough information given.

Question 18

When potassium metal is exposed to air, it forms a coating of potassium oxide, according to the following equation: 4K(s)+ O₂(g)→ 2K₂O(s)If a piece of potassium gains 0.354 g, assuming this gain can be attributed to the above reaction with oxygen, what mass of K₂O formed? Report your answer with the correct number of significant figures and correct units.

Accepted Answer

The answer of When potassium metal is exposed to air,...

Question 19

How much heat energy would be needed to raise the temperature of a 22.3 g sample of aluminum [(C = 0.895 (J/g°C)] from 22.5°C to 55.0°C?

Accepted Answer

A) 20.0 J 
B) 649 J 
C) 725 J 
D) 8.10 x 102 J 
E) not enough information given

Question 20

Nitrogen and hydrogen react together to form ammonia according to the equation: ___N2(g)+ ___H2(g)→ ___NH3(g)(unbalanced)Balance the equation, and determine how many grams of hydrogen reactant would be required to produce 25.0 g of ammonia, assuming there is sufficient nitrogen available.

Accepted Answer

A) 2.23 g 
B) 4.46 g 
C) 2.97 g 
D) 2.40 g 
E) not enough information

Exam 6: Quantities in Chemical Reactions

If the theoretical yield for a reaction is 72.3 g, and 65.2 g of product are actually obtained, what is the percent yield?

Iron metal reacts with chlorine gas according to the following equation: 2Fe(s) + 3Cl₂(g) → 2FeCl₃(s) If 25.6 g each of iron and chlorine are combined, how much FeCl₃ should form?

Which of the following is an exothermic process?

The burning of a 2.50 g sample of pizza in a bomb calorimeter gives off 2.53 x 104 J of energy. If the calorimeter contains 2440 g of water, what was the temperature change of the water? [C_water = 4.184 J/(g°C)] Report your answer with the correct number of significant figures.

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: _P₄(s) + _Cl₂(g) → ___PCl₃(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 10.6 g of phosphorus.

Phosphorus trichloride can be made by the following reaction: P₄(s) + 6Cl₂(g) → 4PCl₃(l) What is the maximum amount of phosphorus trichloride that can be formed if 10 molecules of P₄ are mixed with 36 molecules of chlorine?

The coefficients of a balanced equation can be understood to represent either relative numbers of moles or relative mass.

When 5.0 g CaCl₂ is dissolved in enough water to make a 0.500 L solution, what is the molarity of ions in solution?

When one molecule of propane, C₃H₈, burns in a gas grill, it combines with five oxygen molecules to form three CO₂ molecules and four H₂O molecules. Select the statement below that is incorrect in regard to this reaction.

Given the balanced equation 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) , if 82.0 g of NH₃ react with sufficient oxygen, how many grams of NO should form?

If the theoretical yield for a reaction is 54.9 g, and 51.3 g of product are actually obtained, the percent yield is

How much heat energy would be needed to raise the temperature of a 22.3 g sample of aluminum [(C = 0.895 (J/g°C) ] from 22.5°C to 55.0°C?

Nitrogen and hydrogen react together to form ammonia according to the equation: _N₂(g) + _H₂(g) → ___NH₃(g) (unbalanced) Balance the equation, and determine how many grams of hydrogen reactant would be required to produce 25.0 g of ammonia, assuming there is sufficient nitrogen available.

Exam 6: Quantities in Chemical Reactions

If the theoretical yield for a reaction is 72.3 g, and 65.2 g of product are actually obtained, what is the percent yield?

Iron metal reacts with chlorine gas according to the following equation: 2Fe(s) + 3Cl2(g) → 2FeCl3(s) If 25.6 g each of iron and chlorine are combined, how much FeCl3 should form?

Which of the following is an exothermic process?

The burning of a 2.50 g sample of pizza in a bomb calorimeter gives off 2.53 x 104 J of energy. If the calorimeter contains 2440 g of water, what was the temperature change of the water? [Cwater = 4.184 J/(g°C)] Report your answer with the correct number of significant figures.

When mixed, solutions of copper(II) nitrate, Cu(NO3) 2, and sodium phosphate, Na3PO4, will form a precipitate of copper phosphate, Cu3(PO4) 2. The balanced equation is 3Cu(NO3) 2(aq) + 2Na3PO4(aq) → Cu3(PO4) 2(s) + 6NaNO3(aq) Which of the following statements regarding this reaction is incorrect?

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: ___P4(s) + ___Cl2(g) → ___PCl3(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 10.6 g of phosphorus.

Phosphorus trichloride can be made by the following reaction: P4(s) + 6Cl2(g) → 4PCl3(l) What is the maximum amount of phosphorus trichloride that can be formed if 10 molecules of P4 are mixed with 36 molecules of chlorine?

The coefficients of a balanced equation can be understood to represent either relative numbers of moles or relative mass.

When 5.0 g CaCl2 is dissolved in enough water to make a 0.500 L solution, what is the molarity of ions in solution?

When one molecule of propane, C3H8, burns in a gas grill, it combines with five oxygen molecules to form three CO2 molecules and four H2O molecules. Select the statement below that is incorrect in regard to this reaction.

Given the balanced equation 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) , if 82.0 g of NH3 react with sufficient oxygen, how many grams of NO should form?

If the theoretical yield for a reaction is 54.9 g, and 51.3 g of product are actually obtained, the percent yield is

How much heat energy would be needed to raise the temperature of a 22.3 g sample of aluminum [(C = 0.895 (J/g°C) ] from 22.5°C to 55.0°C?

Nitrogen and hydrogen react together to form ammonia according to the equation: ___N2(g) + ___H2(g) → ___NH3(g) (unbalanced) Balance the equation, and determine how many grams of hydrogen reactant would be required to produce 25.0 g of ammonia, assuming there is sufficient nitrogen available.

Iron metal reacts with chlorine gas according to the following equation: 2Fe(s) + 3Cl₂(g) → 2FeCl₃(s) If 25.6 g each of iron and chlorine are combined, how much FeCl₃ should form?

The burning of a 2.50 g sample of pizza in a bomb calorimeter gives off 2.53 x 104 J of energy. If the calorimeter contains 2440 g of water, what was the temperature change of the water? [C_water = 4.184 J/(g°C)] Report your answer with the correct number of significant figures.

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: _P₄(s) + _Cl₂(g) → ___PCl₃(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 10.6 g of phosphorus.

Phosphorus trichloride can be made by the following reaction: P₄(s) + 6Cl₂(g) → 4PCl₃(l) What is the maximum amount of phosphorus trichloride that can be formed if 10 molecules of P₄ are mixed with 36 molecules of chlorine?

When 5.0 g CaCl₂ is dissolved in enough water to make a 0.500 L solution, what is the molarity of ions in solution?

When one molecule of propane, C₃H₈, burns in a gas grill, it combines with five oxygen molecules to form three CO₂ molecules and four H₂O molecules. Select the statement below that is incorrect in regard to this reaction.

Given the balanced equation 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) , if 82.0 g of NH₃ react with sufficient oxygen, how many grams of NO should form?

Nitrogen and hydrogen react together to form ammonia according to the equation: _N₂(g) + _H₂(g) → ___NH₃(g) (unbalanced) Balance the equation, and determine how many grams of hydrogen reactant would be required to produce 25.0 g of ammonia, assuming there is sufficient nitrogen available.