Question : 1.              When one molecule of propane, C3H8, burns in a : 1335438

1.              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 ? 3CO2 + 4H2O.

B)If five propane molecules react, 15 CO2 molecules will be formed.

C)If five propane molecules react, 25 O2 molecules must also react.

D)If 15 O2 molecules react, 9 H2O molecules will be formed.

E)If 12 CO2 molecules are formed, then four propane molecules must have reacted.

2.              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 ? 2CO2 + 3H2O.

B)If four ethanol molecules react, eight CO2 molecules will be formed.

C)If 12 H2O molecules are formed, then nine 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 will also be formed.

3.              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 ? 4CO2 + 2H2O.

B)If eight acetylene molecules react, 12 CO2 molecules will be formed.

C)If 12 H2O molecules are formed, then 30 O2 molecules must have reacted.

D)If 12 CO2 molecules are formed, then six H2O molecules will also be formed.

E)If  24 ethanol molecules react, then 60 oxygen molecules must also react.

4.              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.

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

A)Na22+(aq) + SO42?(aq)D)Na22+(aq) + S(s) + O42?(aq)

B)2Na2+(aq) + SO42?(aq)E)Na22+(aq) + S2?(aq) + 4O2?(aq)

C)2Na+(aq) + SO42?(aq)

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

A)K22+(aq) + CO32?(aq)D)2K+(aq) + C(s) + O32?(aq)

B)2K2+(aq) + CO32?(aq)E)K22+(aq) + C4+(aq) + 3O2?(aq)

C)2K+(aq) + CO32?(aq)

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

A)(NH4)22+(aq) + CO32?(aq)

B)2NH4+(aq) + CO32?(aq)

C)2N3?(aq) + 4H+(aq) + CO32?(aq)

D)2N3?(aq) + 4H+(aq) + C(s) + O32?(aq)

E)2N3?(aq) + 4H+(aq) + C4+(aq)+ 3O2?(aq)

8.              Which of the following is the best balanced equation to represent the chemical reaction exactly as shown in the figure?

A)4A + 8B ? 12ABD)A2 + B2 ? AB2

B)2A2 + 4B2 ? 4A2BE)A2 + 2B2 ? 2AB2

C)2A2 + 4B2 ? 4AB2

9.              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 ? 16H + 10OD)2H2 + O2 ? 2H2O

B)16H + 10O ? 8H2O + O2E)4H2 + 2O2 ? 4H2O

C)8H2 + 5O2 ? 8H2O + O2

10.              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 ? 12NHD)12N + 12H ? 4NH3 + 8N

B)6N2 + 6H2 ? 4NH3E)N2 + 3H2 ? 2NH3

C)6N2 + 6H2 ? 4NH3 + 4N2

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