Question : 1.              A 5.05 g sample of quartz (SiO2) contains 2.36 : 1335410

1.              A 5.05 g sample of quartz (SiO2) contains 2.36 g of silicon.  What are the percents of silicon and oxygen in quartz?

A)53.3% Si and 46.7% O

B)46.7% Si and 53.3% O

C)29.9% Si and 70.1% O

D)70.1% Si and 29.9% O

E)46.7% Si, and insufficient information to calculate % O

2.              A 6.25 g sample of magnetite (Fe3O4) contains 4.52 g of Fe.  What are the percents of iron and oxygen in magnetite?

A)28.6% Fe and 71.4% OD)27.7% Fe and 72.3% O

B)42.8% Fe and 57.2% OE)57.2% Fe and 42.8% O

C)72.3% Fe and 27.7% O

3.              A 7.50 g sample of pyrite (FeS2) contains 3.49 g of iron.  What are the percents of iron and sulfur in pyrite (also known as “Fool’s Gold” because of its golden color)?

A)57.4% Fe and 42.6% SD)46.5% Fe and 53.5% S

B)66.7% Fe and 33.3% SE)53.5% Fe and 46.5% S

C)33.3% Fe and 66.7% S

4.              Malachite is a green colored mineral that is 57.5% copper.  What mass of copper is present in a 250.0 g sample of malachite?

A)  63.6 g    B)  127 g    C)  435 g    D)  36.5 g    E)  144 g

5.              Barium sulfate is a compound used to assist in diagnosing medical problems through x-ray analysis and is 58.8% barium.  What mass of barium is present in a 620 mg tablet of barium sulfate?

A)  81 mg    B)  230 mg    C)  360 mg    D)  1100 mg    E)  11 mg

6.              Which of the following statements is incorrect?

A)PH3 has 3 times as many hydrogen atoms as phosphorus atoms.

B)MgO has an equal number of magnesium ions and oxygen ions.

C)BaBr2 has half as many barium ions as bromide ions.

D)N2O5 has 2.5 times as many nitrogen atoms as oxygen atoms.

E)SF4 has 4 times as many fluorine atoms as sulfur atoms.

7.              Which of the following statements is incorrect?

A)CH4 has ¼ as many carbon atoms as hydrogen atoms.

B)H2O has twice as many oxygen atoms as hydrogen atoms.

C)SO3 has three times as many oxygen atoms as sulfur atoms.

D)P4O10 has 2.5 times as many oxygen atoms as phosphorus atoms.

E)SrF2 has twice as many fluoride ions as strontium ions.

8.              Which of the following statements is incorrect?

A)N2H4 has four times as many hydrogen atoms as nitrogen atoms.

B)SF4 has ¼ as many sulfur atoms as fluorine atoms.

C)SO2 has twice as many oxygen atoms as sulfur atoms.

D)Ca(NO3)2 has six times as many oxygen atoms as calcium ions.

E)H2SO4 has twice as many oxygen atoms as hydrogen atoms.

9.              Which of the following statements is incorrect?

A)H2SO3 has 1.5 times as many oxygen atoms as hydrogen atoms.

B)Fe2(SO4)3 has six times as many oxygen atoms as iron ions.

C)N2H4 has twice as many hydrogen atoms as nitrogen atoms.

D)MgF2 has half as many fluoride ions as magnesium ions.

E)Carbon dioxide has twice as many oxygen atoms as carbon atoms.

10.              Which of the following sets of formulas is correct for the molecules in the figure?

A)H2SO3, SCl4, C2H4D)H2SO4, SCl4, CH4

B)H2SO3, SCl3, C2H4E)H2SO4, SCl4, C2H4

C)H2SO4, SCl3, C2H4

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