Question : 31.              Given that 4NH3(g) + 5O2(g) ? 4NO(g) + 6H2O(g), : 1335441

31.              Given that 4NH3(g) + 5O2(g) ? 4NO(g) + 6H2O(g), if 32.5 g of NH3 react with sufficient oxygen, how many grams of H2O will be formed?

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

32.              When copper reacts with sulfur at high temperature, copper(I) sulfide is formed.

2Cu(s) + S(s) ?  Cu2S(s)

If the mass of the copper increases by 0.235 g, how many grams of copper reacted?

A)  0.931 g    B)  not enough information    C)  958 g    D)  15.1 g    E)  0.471

33.              When magnesium is heated in air, it reacts with oxygen to form magnesium oxide.

2Mg(s) + O2(g) ?  2MgO(s)

If the mass of the magnesium increases by 0.335 g, how many grams of magnesium reacted?

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

34.              Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt):

2Na(s) + Cl2(g) ?  2NaCl(s)

If the mass of the sodium increases by 0.500 g, how many grams of sodium reacted?

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

35.              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) ? ____ZnSO4(aq) + ___Cu(s)

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

36.              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) ? ____KCl(s) + ___O2(g) (unbalanced)

Balance the equation, and determine the mass of oxygen that will 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

37.              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) ? ____KCl(s) + ___O2(g) (unbalanced)

Balance the equation, and determine the mass of oxygen that will 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

38.              When mercury(II) oxide, a red crystalline solid, is heated, it decomposes to form liquid mercury and oxygen gas, according to the equation:

___HgO(s) ? ___Hg(l) + ___O2(g)  (unbalanced)

Balance the equation and determine the mass of mercury that will 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

39.              When mercury(II) oxide, a red crystalline solid, is heated, it decomposes to form liquid mercury and oxygen gas, according to the equation:

___HgO(s) ? ___Hg(l) + ___O2(g)  (unbalanced)

Balance the equation and determine the mass of mercury that will 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

40.              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.

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