Chemistry Exam 1

 

  1. Which statements are examples of a physical property ?
        1. Ice cream melting.
        2. Burning a wooden log.
        3. Lead weights sink in H2O.
  1. I and II
  2. I and III
  3. II and III
  4. I and II and III
  5. III only

 

2.   If copper has two naturally occurring isotopes, 63Cu (62.9396 amu) with an abundance of 69.50% and 65Cu (64.9278 amu) with an abundance of 30.50%.
What is the average atomic mass of copper ?

  1. 63.4367 amu
  2. 63.5460 amu
  3. 63.7349 amu
  4. 63.9337 amu
  5. 64.3214 amu

 

3.  In the pair of atoms, 60Co and 60Ni, both atoms have the same

  1. Mass number.
  2. Atomic number.
  3. Number of protons.
  4. Number of neutrons.
  5. Number of electrons.

 

4.  What is the correct atomic representation for a species with 10 e-, 8 protons and 10 neutrons?

  1. 16O
  2. 18O
  3. 16O2+ 
  4. 18O2- 
  5. 18Ne2- 

 

5.  What is the formula of a neutral compound of aluminum and sulfide ions?

a.  AlS2 

b.  AlS3 

c.  Al2S

d.  Al2S3 

e.  Al3S2 

 

6.  Which ion is NOT correctly named?

a.  ammonium ion

NH4+ 

b.  carbonate ion

CO32- 

c.  cyanide ion

CN- 

d.  nitrite ion

NO2- 

e.  sulfate ion

SO32- 

 

7.  Which property is characteristic of metalloids ?

  1. They form only cations.
  2. They have a shine or luster.
  3. They are malleable and ductile.
  4. They are electrical semiconductors.
  5. They are often gases at room temperature.

 

8.  A student heats 1.00 g of a blue compound and obtains 0.64 g of a white compound and some colorless gas in a complete reaction. How many grams of the gas are formed ?

  1. 0.36 g
  2. 0.64 g
  3. 1.00 g
  4. 1.64 g
  5. More information is needed to work this problem.

 

9.  How many moles of Pt(NH3)2Cl2, a cancer drug, are in 136.5 g of Pt(NH3)2Cl2 ?

  1. 0.0756 moles
  2. 0.455 moles
  3. 0.482 moles
  4. 2.20 moles
  5. 2.73 moles

 

10.  Sulfur consists of rings consisting of 8 sulfur atoms. What is the best classification for sulfur?

  1. impure mixture
  2. atomic element
  3. ionic compound
  4. molecular element
  5. molecular compound

 

11. How many oxygen atoms are found in 0.40 moles of NaHCO3 ?

  1. 8.0 1022 atoms
  2. 2.4 1023 atoms
  3. 4.8 1023 atoms
  4. 7.2 1023 atoms
  5. 1.4 1024 atoms

 

12.  What is the empirical formula of a compound which contains 36.86% N and 63.14% O ?

  1. NO2 
  2. N2O
  3. N2O3 
  4. N2O5 
  5. N3O4 

 

13.  What is the sum of the coefficients when the chemical equation below is balanced?

__ Bi2O3(s)  +  __ C(s)       __ Bi(s)  +  __ CO(g)

    1. 4
    2. 5
    3. 8
    4. 9
    5. 10

 

14.  The term "carbohydrate" once meant a compound with the empirical formula of CH2O. What is the molecular formula of ribose, a carbohydrate, which has a molecular weight of 150.13 g/mol.

  1. C2H4O2 
  2. C3H6O3 
  3. C4H8O4 
  4. C5H10O5 
  5. C6H12O6 

 

15.  How many moles of O2 are needed to react with 304.5 g of CS2 in the combustion reaction below?

CS2(l)  +  3 O2(g)      CO2(g)  +  2 SO2(g)

  1. 1.33 mol
  2. 4.00 mol
  3. 6.00 mol
  4. 8.00 mol
  5. 12.0 mol

 

16.  How many grams of H2O will form when 10.0 g of NH3 mixes with 10.0 g of O2 according to the reaction below ?

4 NH3(g)  +  5 O2(g)      4 NO(g)   +  6 H2O(l)

  1. 5.62 g
  2. 6.75 g
  3. 10.6 g
  4. 13.5 g
  5. 15.9 g

 

17.  Which statement(s) below are TRUE?

    1. One 12C atom weighs 12.0000 grams.
    2. A mole of CH4 has the same number of molecules as a mole of C8H16.
    3. The limiting reagent is the reactant present in the smallest amount initially.
  1. I and II
  2. I and III
  3. II and III
  4. I and II and III
  5. II only

 

18.  BONUS: When 56.6 g of Ca and 30.5 g of N2 react, only 90.0% of the product is recovered. What mass of Ca3N2 is recovered from this reaction ?

3 Ca(s)  +  N2(g)      Ca3N2(s)

  1. 62.8 g
  2. 69.8 g
  3. 78.4 g
  4. 145 g
  5. 161 g