Deck 6: Quantities in Chemical Reactions

Question 1

Consider the reaction between hydrogen and oxygen gases to form water: 2H₂(g) + O₂(g) $\rightarrow$ 2H₂O(l) Which of the following is not conserved in this reaction?

A)atoms
B)moles of atoms
C)moles of molecules
D)mass

Answer 1

moles of molecules

Question 2

Consider the reaction between acetylene, C₂H₂, and oxygen in a welding torch: 2C₂H₂(g) + 5O₂(g) $\rightarrow$ 4CO₂(g) + 2H₂O(g) Which of the following is not conserved in this reaction?

A)atoms
B)moles of atoms
C)moles of molecules
D)mass

Answer 2

moles of molecules

Question 3

Consider the reaction between sodium metal and chlorine gas to form sodium chloride: 2Na(s) + Cl₂(g) $\rightarrow$ 2NaCl(s) Which of the following is not conserved in this reaction?

A)atoms
B)moles of atoms
C)moles of molecules
D)mass

Answer 3

moles of molecules

Question 4

When the mixture of molecules shown in the molecular-level image undergoes complete reaction, all of these molecules are converted to products.Which of the following reactions could this represent?

A)2N₂ + 3O₂ $\rightarrow$ 2N₂O₃
B)N₂ + 2Cl₂ $\rightarrow$ N₂Cl₄
C)O₂ + 2H₂ $\rightarrow$ 2H₂O
D)N₂ + 3Cl₂ $\rightarrow$ 2NCl₃
E)3N₂ + 2H₂ $\rightarrow$ 3N₂H₄

Question 5

When mixed, solutions of aluminum nitrate, Al(NO₃)₃, and ammonium carbonate, (NH₄)₂CO₃, will form a precipitate of aluminum carbonate, Al₂(CO₃)₃.The balanced equation is 2Al(NO₃)₃(aq) + 3(NH₄)₂CO₃(aq) $\rightarrow$ Al₂(CO₃)₃ (s) + 6NH₄NO₃(aq) Which of the following statements regarding this reaction is incorrect?

A)2 moles of Al(NO₃)₃ will react with 3 moles of (NH₄)₂CO₃.
B)If 6 moles of (NH₄)₂CO₃ react with sufficient Al(NO₃)₃, 2 moles of Al₂(CO₃)₃ should form.
C)If 0.5 mole of (NH₄)₂CO₃ react with sufficient Al(NO₃)₃, 3 moles of Al₂(CO₃)₃ should form.
D)If 1.5 moles of Al₂(CO₃)₃ are formed, given sufficient starting materials, then 9 moles of NH₄NO₃ should also form.
E)4 moles of Al(NO₃)₃ will react with 6 moles of (NH₄)₂CO₃.

Question 6

Which of the following is the best (simplest) balanced equation to represent the chemical reaction shown in the figure on any scale?

A)12N + 12H $\rightarrow$ 12NH
B)6N₂ + 6H₂ $\rightarrow$ 4NH₃
C)6N₂ + 6H₂ $\rightarrow$ 4NH₃ + 4N₂
D)12N + 12H $\rightarrow$ 4NH₃ + 8N
E)N₂ + 3H₂ $\rightarrow$ 2NH₃

Question 7

When acetylene, C₂H₂, a fuel used in welding, is burned in air, two molecules of acetylene combine with five oxygen molecules to form four CO₂ molecules and two H₂O molecules.Select the statement below that is incorrect in regard to this reaction.

A)The balanced equation for the reaction is 2C₂H₂ + 5O₂ $\rightarrow$ 4CO₂ + 2H₂O.
B)If 8 acetylene molecules react, 12 CO₂ molecules should form.
C)If 12 H₂O molecules are formed, then 30 O₂ molecules must have reacted.
D)If 12 CO₂ molecules are formed, then 6 H₂O molecules should also form.
E)If 24 ethanol molecules react, then 60 oxygen molecules must also react

Question 8

Which of the following is the best (simplest) balanced equation to represent the chemical reaction shown in the figure on any scale?

A)4A + 8B $\rightarrow$ 12AB
B)2A₂ + 4B₂ $\rightarrow$ 4A₂B
C)2A₂ + 4B₂ $\rightarrow$ 4AB₂
D)A₂ + B₂ $\rightarrow$ AB₂
E)A₂ + 2B₂ $\rightarrow$ 2AB₂

Question 9

Which of the following equations is balanced?

A)P₄(s) + 10O₂(g) $\rightarrow$ P₄O₁₀(s)
B)ZnS(s) + 3O₂(g) $\rightarrow$ ZnO(s) + 2SO₂(g)
C)NH₃(g) + O₂(g) $\rightarrow$ NO₂(g) + H₂O(g)
D)4KBrO₃(s) $\rightarrow$ 3KBrO₄(s) + KBr(s)
E)2Na(s) + P(s) $\rightarrow$ Na₃P(s)

Question 10

When ammonium carbonate, (NH₄)₂CO₃, dissolves in water, the ions that are formed for each formula unit that dissolves are:

A)(NH₄)₂²⁺(aq) + CO₃^2-(aq)
B)2NH₄⁺(aq) + CO₃^2-(aq)
C)2N^3-(aq) + 4H⁺(aq) + CO₃^2-(aq)
D)2N^3-(aq) + 4H⁺(aq) + C(s) + O₃^2-(aq)
E)2N^3-(aq) + 4H⁺(aq) + C⁴⁺(aq)+ 3O^2-(aq)

Question 11

When mixed, solutions of silver nitrate, AgNO₃, and sodium phosphate, Na₃PO₄, will form a precipitate of silver phosphate, Ag₃PO₄.The balanced equation is 3AgNO₃(aq) + Na₃PO₄(aq) $\rightarrow$ Ag₃PO₄(s) + 3NaNO₃(aq) Which of the following statements regarding this reaction is incorrect?

A)6 moles of AgNO₃ will react with 2 moles of Na₃PO₄.
B)9 moles of AgNO₃ should react to form 2 moles of Ag₃PO₄, given sufficient Na₃PO₄.
C)1.5 moles of NaNO₃ should form when 0.5 mole of Na₃PO₄ reacts with sufficient AgNO₃.
D)3 moles of Ag₃PO₄ should form when 3 moles of Na₃PO₄ react with sufficient AgNO₃.
E)2 moles of Na₃PO₄ will react with 6 moles of AgNO₃.

Question 12

All of the following may change during a chemical reaction except

A)the total number of atoms in the system.
B)the temperature of the system.
C)the color of the system.
D)the total number of molecules in the system.
E)the physical state of the system.

Question 13

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) $\rightarrow$ Cu₃(PO₄)₂(s) + 6NaNO₃(aq) Which of the following statements regarding this reaction is incorrect?

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 14

When potassium carbonate, K₂CO₃, dissolves in water, the ions that are formed for each formula unit that dissolves are:

A)K₂²⁺(aq) + CO₃^2-(aq)
B)2K²⁺(aq) + CO₃^2-(aq)
C)2K⁺(aq) + CO₃^2-(aq)
D)2K⁺(aq) + C(s) + O₃^2-(aq)
E)K₂²⁺(aq) + C⁴⁺(aq) + 3O^2-(aq)

Question 15

Which of the following is the best (simplest) balanced equation to represent the chemical reaction shown in the figure on any scale?

A)16H + 10O $\rightarrow$ 16H + 10O
B)16H + 10O $\rightarrow$ 8H₂O + O₂
C)8H₂ + 5O₂ $\rightarrow$ 8H₂O + O₂
D)2H₂ + O₂ $\rightarrow$ 2H₂O
E)4H₂ + 2O₂ $\rightarrow$ 4H₂O

Question 16

When the mixture of molecules shown in the molecular-level image undergoes complete reaction, all of these molecules are converted to products.Which of the following reactions could this represent?

A)N₂ + O₂ $\rightarrow$ 2NO
B)N₂ + 2Cl₂ $\rightarrow$ N₂Cl₄
C)N₂ + 2O₂ $\rightarrow$ 2NO₂
D)N₂ + 3H₂ $\rightarrow$ 2NH₃
E)N₂ + 3O₂ $\rightarrow$ 2NO₃

Question 17

Phosphine, PH₃, a reactive and poisonous compound, reacts with oxygen as follows: 4PH₃(g) + 8O₂(g) $\rightarrow$ P₄O₁₀(s) + 6H₂O(g) If 9.2 moles of phosphine react with sufficient oxygen, how many moles of P₄O₁₀ should form?

A)4.0 moles
B)9.2 moles
C)37 moles
D)2.3 moles
E)6.0 moles

Question 18

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.

A)The balanced equation for the reaction is C₃H₈ + 5O₂ $\rightarrow$ 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 19

When sodium sulfate, Na₂SO₄, dissolves in water, the ions that are formed for each formula unit that dissolves are:

A)Na₂²⁺(aq) + SO₄^2-(aq)
B)2Na²⁺(aq) + SO₄^2-(aq)
C)2Na⁺(aq) + SO₄^2-(aq)
D)Na₂²⁺(aq) + S(s) + O₄^2-(aq)
E)Na₂²⁺(aq) + S^2-(aq) + 4O^2-(aq)

Question 20

When ethanol, C₂H₅OH, a component in some gasoline mixtures, is burned in air, one molecule of ethanol combines with three oxygen molecules to form two CO₂ molecules and three H₂O molecules.Select the statement below that is incorrect in regard to this reaction.

A)The balanced equation for the reaction is C₂H₅OH + 3O₂ $\rightarrow$ 2CO₂ + 3H₂O.
B)If 4 ethanol molecules react, 8 CO₂ molecules should form.
C)If 12 H₂O molecules are formed, then 9 O₂ molecules must have reacted.
D)If 15 ethanol molecules react, then 45 oxygen molecules must also react.
E)If 12 CO₂ molecules are formed, then 18 H₂O molecules should also form.

Question 21

Given the balanced equation 4NH₃(g) + 5O₂(g) $\rightarrow$ 4NO(g) + 6H₂O(g), if 32.5 g of NH₃ react with sufficient oxygen, how many grams of H₂O should form?

A)51.6 g
B)8.60 g
C)34.4 g
D)206.4 g
E)878 g

Question 22

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) $\rightarrow$ ___Hg(l) + ___O₂(g) (unbalanced) Balance the equation and determine the mass of mercury that should be formed when 15.6 g of HgO is heated.

A)28.9 g
B)7.22 g
C)14.4 g
D)16.9 g
E)13.2 g

Question 23

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt): 2Na(s) + Cl₂(g) $\rightarrow$ 2NaCl(s) If 12.5 g of sodium react with sufficient chlorine, how many grams of sodium chloride should form?

A)15.9 g
B)31.8 g
C)63.6 g
D)4.92 g
E)9.84 g

Question 24

Small amounts of oxygen gas can be produced for laboratory use by heating potassium chlorate, which causes it to decompose by the following reaction: ___KClO₃(s) $\rightarrow$ _{____}KCl(s) + ___O₂(g) (unbalanced) Balance the equation, and determine the mass of oxygen that should be formed if 10.0 g of potassium chlorate decomposes.

A)7.83 g
B)115 g
C)3.92 g
D)38.3 g
E)57.4 g

Question 25

When copper reacts with sulfur at high temperature, copper(I) sulfide is formed. 2Cu(s) + S(s) $\rightarrow$ Cu₂S(s) If the mass of the Cu₂S formed is 1.17 g, what mass of copper should have reacted?

A)0.934 g
B)not enough information
C)0.78 g
D)2.34 g
E)0.467 g

Question 26

When magnesium is heated in air, it reacts with oxygen to form magnesium oxide: 2Mg(s) + O₂(g) $\rightarrow$ 2MgO(s) If the mass of the magnesium solid increases by 0.335 g, what mass of magnesium metal should have reacted?

A)0.882 g
B)0.441 g
C)0.509 g
D)1.02 g
E)not enough information

Question 27

Consider the reaction between hydrogen and oxygen gases to form water: 2H₂(g) + O₂(g) $\rightarrow$ 2H₂O(l) If 8.5 moles of oxygen react with sufficient hydrogen, how many grams of water should form?

A)0.94 g
B)0.47 g
C)76 g
D)3.1 x 10² g
E)1.5 x 10² g

Question 28

Consider the reaction between acetylene, C₂H₂, and oxygen in a welding torch: 2C₂H₂(g) + 5O₂(g) $\rightarrow$ 4CO₂(g) + 2H₂O(g) If 5.4 moles of acetylene react with sufficient oxygen, how many grams of CO₂ should form?

A)2.4 x 10² g
B)9.5 x 10² g
C)4.8 x 10² g
D)1.5 x 10² g
E)0.49 g

Question 29

Given that 4NH₃(g) + 5O₂(g) $\rightarrow$ 4NO(g) + 6H₂O(g), if 4.5 moles of NH₃ react with sufficient oxygen, how many moles of H₂O should form?

A)4.0
B)4.5
C)6.0
D)6.8
E)5.5

Question 30

Phosphine, PH₃, a reactive and poisonous compound, reacts with oxygen as follows: 4PH₃(g) + 8O₂(g) $\rightarrow$ P₄O₁₀(s) + 6H₂O(g) If you need to make 6.5 moles of P₄O₁₀ , how many moles of PH₃ is required for the reaction?

A)6.5 moles
B)13 moles
C)26 moles
D)3.2 moles
E)1.6 moles

Question 31

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt): 2Na(s) + Cl₂(g) $\rightarrow$ 2NaCl(s) If 3.6 moles of chlorine react with sufficient sodium, how many grams of sodium chloride should form?

A)1.1 x 10² g
B)2.1 x 10² g
C)4.2 x 10² g
D)0.13 g
E)0.062 g

Question 32

Given that 4NH₃(g) + 5O₂(g) $\rightarrow$ 4NO(g) + 6H₂O(g), if 8.2 moles of NH₃ react with sufficient oxygen, how many moles of water should form?

A)6.0 moles
B)4.0 moles
C)5.0 moles
D)12 moles
E)8.2 moles

Question 33

Phosphine, PH₃, a reactive and poisonous compound, reacts with oxygen as follows: 4PH₃(g) + 8O₂(g) $\rightarrow$ P₄O₁₀(s) + 6H₂O(g) If 15.0 g of phosphine reacts with sufficient oxygen, how many grams of P₄O₁₀ will be formed?

A)125 g
B)31.3 g
C)5.00 x 10² g
D)18.9 g
E)75.7 g

Question 34

Given that 4NH₃(g) + 5O₂(g) $\rightarrow$ 4NO(g) + 6H₂O(g), if 6.3 moles of NH₃ react with sufficient oxygen, how many moles of NO should form?

A)4.0 moles
B)6.3 moles
C)6.0 moles
D)5.0 moles
E)3.2 moles

Question 35

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

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

Question 36

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) $\rightarrow$ ___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.

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

Question 37

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

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

Question 38

When a 0.525 g piece of zinc is placed in a solution of copper(II) sulfate, copper metal and zinc sulfate are formed.Balance the equation for the reaction, and determine the mass of copper(II) sulfate that would react with this quantity of zinc. ___ Zn(s) + ___CuSO₄(aq) $\rightarrow$ _{___}ZnSO₄(aq) + ___Cu(s) (unbalanced)

A)65.4 g
B)0.641 g
C)1.28 g
D)2.56 g
E)159 g

Question 39

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt): 2Na(s) + Cl₂(g) $\rightarrow$ 2NaCl(s) If the mass of the sodium solid increases by 0.500 g, what mass of sodium metal should have reacted?

A)0.250 g
B)0.500 g
C)0.0811 g
D)0.162 g
E)0.324 g

Question 40

Small amounts of oxygen gas can be produced for laboratory use by heating potassium chlorate, which causes it to decompose by the following reaction: ___KClO₃(s) $\rightarrow$ _{____}KCl(s) + ___O₂(g) (unbalanced) Balance the equation, and determine the mass of oxygen that should be formed if 15.0 g of potassium chlorate decomposes.

A)11.7 g
B)57.5 g
C)173 g
D)5.88 g
E)86.1 g

Question 41

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the following equation: ___P₄(s) + ___Cl₂(g) $\rightarrow$ ___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.

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

Question 42

Ammonia is usually made by the following reaction: N₂(g) + 3H₂(g) $\rightarrow$ 2NH₃(g) What is the maximum amount of ammonia that can be formed if 25 molecules of nitrogen are mixed with 60 molecules of hydrogen?

A)20 molecules
B)25 molecules
C)30 molecules
D)40 molecules
E)85 molecules

Question 43

Phosphorus trichloride can be made by the following reaction: P₄(s) + 6Cl₂(g) $\rightarrow$ 4PCl₃(l) What is the maximum amount of phosphorus trichloride that can be formed if 15 molecules of P₄ are mixed with 42 molecules of chlorine?

A)4 molecules
B)12 molecules
C)24 molecules
D)28 molecules
E)57 molecules

Question 44

If you have eight bicycle wheels and five frames, how many bikes could you build (assuming that each bike requires one frame and two wheels), and what would be left over?

A)Four bikes could be built, and nothing would be left over.
B)Four bikes could be built, and one frame would be left over.
C)Five bikes could be built, and three wheels would be left over.
D)Five bikes could be built, and nothing would be left over.
E)Three bikes could be built, and two frames would be left over.

Question 45

Nitrogen and hydrogen react together to form ammonia according to the following equation: ___N₂(g) + ___H₂(g) $\rightarrow$ ___NH₃(g) (unbalanced) Balance the equation, and determine how many grams of hydrogen reactant would be required to produce 50.0 g of ammonia, assuming there is sufficient nitrogen available.

A)4.46 g
B)5.94 g
C)4.81 g
D)8.91 g
E)not enough information

Question 46

Consider the following reaction: Cr₂O₃(s) + 3CCl₄(l) $\rightarrow$ 2CrCl₃(s) + 3COCl₂(g) green colorless purple colorless solid liquid solid gas When the green solid is mixed with the colorless liquid, the mixture starts to bubble and fume.When all action has stopped, a dry purple solid containing solid green specks remains.Which substance is the limiting reactant?

A)Cr₂O₃
B)CCl₄
C)CrCl₃
D)COCl₂
E)there is no limiting reactant

Question 47

Ammonia is usually made by the following reaction: N₂(g) + 3H₂(g) $\rightarrow$ 2NH₃(g) What is the maximum amount of ammonia that can be formed if 30 molecules of nitrogen are mixed with 100 molecules of hydrogen?

A)20 molecules
B)30 molecules
C)40 molecules
D)60 molecules
E)70 molecules

Question 48

A pamphlet requires one cover, 14 pieces of white paper, and three sheets of colored paper.How many pamphlets could be made, and what would be left over, if there are 50 covers, 500 sheets of white paper, and 100 sheets of colored paper available?

A)33 pamphlets could be made, and one sheet of colored paper, 38 sheets of white paper, and 17 covers would be left over.
B)50 pamphlets could be made, and there would be no leftovers.
C)650 pamphlets could be made, and there would be no leftovers.
D)34 pamphlets could be made, and 24 sheets of white paper and 16 covers would be left over.
E)35 pamphlets could be made, and 10 sheets of white paper and 15 covers would be left over.

Question 49

Nitrogen and hydrogen react together to form ammonia according to the equation: ___N₂(g) + ___H₂(g) $\rightarrow$ ___NH₃(g) (unbalanced) Balance the equation, and determine how many grams of hydrogen would be required to react with 25.2 g of nitrogen.

A)1.82 g
B)3.64 g
C)5.45 g
D)1.34 g
E)0.891

Question 50

If you wish to make sandwiches which consist of two slices of bread, one ham slice, and three pickle slices, how many sandwiches could you make if you have 12 slices of bread, five slices of ham, and 20 pickle slices, and what would be left over?

A)Six sandwiches could be made, and two pickle slices would be left over.
B)Four sandwiches could be made, and four slices of bread and eight pickle slices would be left over.
C)Five sandwiches could be made, and two slices of bread and five pickle slices would be left over.
D)Twelve sandwiches could be made, and there would be no leftovers.
E)Five sandwiches could be made, and two slices of bread and no pickle slices would be left over.

Question 51

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?

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

Question 52

Nitrogen and hydrogen react together to form ammonia according to the equation: ___N₂(g) + ___H₂(g) $\rightarrow$ ___NH₃(g) (unbalanced) Balance the equation, and determine how many grams of hydrogen would be required to react with 50.4 g of nitrogen.

A)10.9 g
B)3.64 g
C)7.28 g
D)2.68 g
E)1.78 g

Question 53

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: ___P₄(s) + ___Cl₂(g) $\rightarrow$ ___PCl₃(l) (unbalanced) Balance the equation and determine how many grams of phosphorus reactant would be required to produce 25.0 g of phosphorus trichloride, assuming there is sufficient chlorine available.

A)22.6 g
B)45.1 g
C)5.64 g
D)111 g
E)90.2 g

Question 54

Nitrogen and hydrogen react together to form ammonia according to the equation: ___N₂(g) + ___H₂(g) $\rightarrow$ ___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.

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

Question 55

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the following equation: ___P₄(s) + ___Cl₂(g) $\rightarrow$ ___PCl₃(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 21.2 g of phosphorus.

A)12.1 g
B)48.6 g
C)37.0 g
D)148 g
E)72.8 g

Question 56

Consider the following reaction: CrCl₃(s) + KCl(s) + 2H₂SO₄(l) $\rightarrow$ 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?

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

Question 57

When 5.0 g CaCl₂ is dissolved in water, how many moles of ions are in solution?

A)0.135 mole
B)0.045 mole
C)5.0 moles
D)15.0 moles
E)1660 moles

Question 58

Consider the following reaction: Cr₂O₃(s) + 3CCl₄(l) $\rightarrow$ 2CrCl₃(s) + 3COCl₂(g) green colorless purple colorless solid liquid solid gas When the green solid is mixed with the colorless liquid, the mixture starts to bubble and fume.When all action has stopped, a wet purple solid remains.Which substance is the limiting reactant?

A)Cr₂O₃
B)CCl₄
C)CrCl₃
D)COCl₂
E)there is no limiting reactant

Question 59

Phosphorus trichloride can be made by the following reaction: P₄(s) + 6Cl₂(g) $\rightarrow$ 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?

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

Question 60

When 3.0 mol CaCl₂ dissolves in water, how many moles of ions are in solution?

A)1.0 mole
B)3.0 moles
C)6.0 moles
D)9.0 moles
E)12 moles

Question 61

Consider the following reaction: 3NO₂(g) + H₂O(l) $\rightarrow$ 2HNO₃(l) + NO(g) How many moles of NO₂ are required to react with 1.50 moles of H₂O to form 3.00 moles of HNO₃?

A)1.50 mol
B)3.00 mol
C)4.00 mol
D)4.50 mol
E)9.00 mol

Question 62

The figure shows a molecular-level diagram of reactant molecules for the reaction: 2C₂H₂(g) + 5O₂(g) $\rightarrow$ 4CO₂(g) + 2H₂O(g) List the number and formulas of the molecules that should be present after the reaction takes place.

A)4CO₂ + 2H₂O
B)4CO₂ + 2H₂O + 2C₂H₂
C)4CO₂ + 2H₂O + 2C₂H₂ + 5O₂
D)6CO₂ + 3H₂O + 3O₂
E)8CO₂ + 4H₂O + 2C₂H₂

Question 63

Aluminum metal reacts with sulfuric acid according to the following equation: 2Al(s) + 3H₂SO₄(aq) $\rightarrow$ Al₂(SO₄)₃(s) + 3H₂(g) If 12.9 g of aluminum reacts with excess sulfuric acid, and 62.4 g of Al₂(SO₄)₃ are collected, what is the percent yield of Al₂(SO₄)₃?

A)81.8%
B)49.5%
C)76.3%
D)131%
E)not enough information given

Question 64

Aluminum metal reacts with sulfuric acid according to the following equation: 2Al(s) + 3H₂SO₄(aq) $\rightarrow$ Al₂(SO₄)₃(s) + 3H₂(g) If 10.0 g of aluminum reacts with excess sulfuric acid, and 54.2 g of Al₂(SO₄)₃ are collected, what is the percent yield of Al₂(SO₄)₃?

A)63.4%
B)85.5%
C)117%
D)47.1%
E)not enough information given

Question 65

Aluminum reacts with oxygen according to the following reaction: 4Al(s) + 3O₂(g) $\rightarrow$ 2Al₂O₃(s) If 24 moles of aluminum are combined with 12 moles of oxygen, how many moles of Al₂O₃ should form?

A)4.0 moles
B)8.0 moles
C)6.0 moles
D)5.0 moles
E)26 moles

Question 66

The figure shows a molecular-level diagram of reactant molecules for the reaction 2H₂(g) + O₂(g) $\rightarrow$ 2H₂O(l) List the number and formulas of the molecules that should be present after the reaction takes place.

A)2H₂O + 6H₂ + 2O₂
B)3H₂O + 5H₂ + O₂
C)4H₂O + 4H₂ + O₂
D)6H₂O + 2H₂ + O₂
E)6H₂O + 2H₂

Question 67

In the process of obtaining lead from PbS, or galena, the galena is "roasted" (heated in the presence of oxygen), so that the following reaction occurs: 2PbS(s) + 3O₂(g) $\rightarrow$ 2PbO(s) + 2SO₂(g) If 35.2 g of PbS is mixed with 15.5 g of oxygen, how many grams of PbO should form?

A)32.8 g
B)72.1 g
C)105 g
D)65.7 g
E)49.2 g

Question 68

Nitrogen monoxide reacts with oxygen according to the following reaction: 2NO(g) + O₂(g) $\rightarrow$ 2NO₂(g) If 12 moles of nitrogen monoxide are combined with 10 moles of oxygen, how many moles of NO₂ should form?

A)2 moles
B)5 moles
C)6 moles
D)10 moles
E)12 moles

Question 69

Nitrogen monoxide reacts with oxygen according to the following reaction: 2NO(g) + O₂(g) $\rightarrow$ 2NO₂(g) If 10 moles of nitrogen monoxide are combined with 4 moles of oxygen, how many moles of NO₂ should form?

A)4 moles
B)8 moles
C)10 moles
D)12 moles
E)14 moles

Question 70

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

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

Question 71

Consider the reaction N₂(g) + O₂(g) $\rightarrow$ 2NO(g).The molecular image represents a mixture of N₂(g) and O₂(g) just before reaction occurs.What is the limiting reactant, and how much of the excess reactant remains after the reaction is complete? The image contains 2 N₂ molecules and 4 O₂ molecules.

A)N₂(g), 1 O₂(g)
B)N₂(g), 2 O₂(g)
C)N₂(g), 3 O₂(g)
D)O₂(g), 1 N₂(g)
E)N₂(g), 0 O₂(g)

Question 72

Consider the following reaction: 3NO₂(g) + H₂O(l) $\rightarrow$ 2HNO₃(l) + NO(g) How many moles of the excess reactant remain if 4.00 moles of H₂O and 10.00 moles of NO₂ are mixed?

A)0.67 mol H₂O
B)2.00 mol NO₂
C)3.33 mol H₂O
D)6.00 mol NO₂
E)8.00 mol NO₂

Question 73

Iron metal reacts with hydrochloric acid as follows: 2Fe(s) + 6HCl(aq) $\rightarrow$ 2FeCl₃(aq) + 3H₂(g) If 35.6 g of iron react with excess HCl, and 98.6 g of FeCl₃ are collected, what is the percent yield of FeCl₃?

A)103%
B)104%
C)95.7%
D)63.0%
E)not enough information given

Question 74

Iron metal reacts with hydrochloric acid as follows: 2Fe(s) + 6HCl(aq) $\rightarrow$ 2FeCl₃(aq) + 3H₂(g) If 22.4 g of iron react with excess HCl, and 59.4 g of FeCl₃ are collected, what is the percent yield of Al₂(SO₄)₃?

A)65.0%
B)109%
C)91.4%
D)73.0%
E)not enough information given

Question 75

Iron metal reacts with chlorine gas according to the following equation: 2Fe(s) + 3Cl₂(g) $\rightarrow$ 2FeCl₃(s) If 35.0 g each of iron and chlorine are combined, how much FeCl₃ should form?

A)102 g
B)155 g
C)53.4 g
D)80.0 g
E)68.0 g

Question 76

What mass (in grams) of SF₆ should be produced by the following reaction if 7.00 g of sulfur is mixed with 9.00 g of fluorine? S + 3F₂ $\rightarrow$ SF₆

A)24.0
B)6.40
C)11.1
D)32.0
E)16.0

Question 77

Consider the reaction N₂(g) + 2O₂(g) $\rightarrow$ 2NO₂(g).The molecular image represents a mixture of N₂(g) and O₂(g) just before reaction occurs.What is the limiting reactant, and how much of the excess reactant remains after the reaction is complete? The image contains 3 N₂ molecules and 9 O₂ molecules.

A)N₂(g), 6 O₂(g)
B)O₂(g), 1 N₂(g)
C)N₂(g), 3 O₂(g)
D)O₂(g), 2 N₂(g)
E)N₂(g), 7 O₂(g)

Question 78

Aluminum reacts with oxygen according to the following reaction: 4Al(s) + 3O₂(g) $\rightarrow$ 2Al₂O₃(s) If 12 moles of aluminum are combined with 6 moles of oxygen, how many moles of Al₂O₃ should form?

A)4 moles
B)8 moles
C)6 moles
D)12 moles
E)20 moles

Question 79

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

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

Question 80

In the process of obtaining lead from PbS, or galena, the galena is "roasted" (heated in the presence of oxygen), so that the following reaction occurs: 2PbS(s) + 3O₂(g) $\rightarrow$ 2PbO(s) + 2SO₂(g) If 50.0 g of PbS are mixed with 25.0 g of oxygen, how many grams of PbO should form?

A)116 g
B)46.6 g
C)163 g
D)69.9 g
E)93.2 g