TTU General Chemistry

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Chem 111 - Quiz 2C - Fall, 1997
Chapter II: Chemical Formulas and Compound Stoichiometry

1. Which of the following statements are TRUE?

1) Under normal conditions nitrogen exists as a diatomic molecule.
2) Ca(NO)3 is an ionic solid.
3) An ionic solid always consists of cations and anions in equal numbers.

a) only 1
b) 2 and 3
c) 1 and 2
d) 1, 2, and 3

2. Which of the following ion/name combinations is NOT CORRECT?

a) NO3-/nitrate
b) SO42-/sulfate
c) NH4+/ammonia
d) PO43-/phosphate

3. How many moles of silver atoms are in 0.780 grams of silver?

a) 0.78 moles
b) 0.00723 moles
c) 84.2 moles
d) 0.522 moles

4. What is the formula weight of Mg(BrO4)2?

a) 312 amu
b) 232 amu
c) 168.2 amu
d) 477 amu

5. What mass of the compound FeWO4 contains 50.0 grams of tungsten (atomic symbol W, atomic number = 74)?

a) 30.0 g FeWO4
b) 304 g FeWO4
c) 82.6 g FeWO4
d) 188 g FeWO4

6. Which of the following is NOT an ionic compound?

a) LiF
b) CCl4
c) NH4Cl
d) FeSO4

7. A compound contains 20.2% magnesium, 39.8% titanium, and 40.0% oxygen by mass. What is the empirical formula of this compound?

a) MgTiO
b) MgTi2O3
c) Mg2TiO4
d) MgTiO3

8. Which of the following DOES NOT contain 4.00 moles of oxygen atoms?

a) 2.00 moles of CO2
b) 128.0 g of SO2
c) 0.40 moles of P4O10
d) 4.00 moles of KClO3

9. A compound has an empirical formula of C2HBr. If the molar mass of the compound is 314.7 g/mol, what is the molecular formula of the compound?

a) C2HBr
b) C4H2Br2
c) C6H3Br3
d) C8H4Br4

10. A doubly negative ion, symbolized by X2-, forms a compound with a metal M, of the formula M2X. What is the charge on the metal, M?

a) +1
b) +2
c) +3
d) +4

11. What is the mass percent of copper in the mineral bornite, Cu4FeS4?

a) 44.4%
b) 58.0%
c) 14.5%
d) 72.4%

12. Which of the following is the empirical formula for the compound iron(II) carbonate?

a) Fe(CO3)2
b) FeCO3
c) Fe2CO3
d) Fe2(CO3)2

13. A 0.2420 sample of an unknown containing C, O, and H is burned completely. Analysis shows that 0.2265 grams of water are produced. How many grams of hydrogen were present in the 0.2420 grams of sample?

a) 0.0253 grams
b) 0.2265 grams
c) 0.0127 grams
d) 0.1522 grams

14. What is the mass of 0.220 moles of AgNO3?

a) 169.9 g
b) 0.415 g
c) 0.220 g
d) 37.4 g

KEY

1)c 2)c 3)b 4)a 5)c 6)b 7)d 8)d 9)c 10)a 11)b 12)b 13)a 14)d