Prince George S Community College s2
1
Prince George’s Community College
CHM 1010 NAME
EXAM 2
I. Multiple choices: select the best answer for each of the following questions or statements. (20)
1. How many moles of Na in 3.011 x 1023 atoms of sodium ?
a. 1 b. 0.5 c. 2 d. 23
2. Which of the following exist in atom’s nucleus ?
a. Neutrons and protons
b. Protons and electrons
c. Neutrons and electrons
d. None of the above
3. The mass of 5.6 x 1021 sodium atoms is
a. 0.21mg b. 210 mg c. 23 g d. 2.10 g
4. How many hydrogen atoms are in this NH4C2H3O2 formula?
a. 14 b. 3 c. 4 d. 7
5. Which of the following element is not identified as an alkali metal ?
a. sodium b. copper c. Potassium d. Lithium
6 Which of the following will have chemical properties similar to Aluminum?
a. argon (Ar) b. Boron (B) c. nitrogen (N) d. selenium (Se)
7. CaO + CO2 CaCO3 is an example of which type of reaction:
a. synthesis b. acid-base c. decomposition d. oxidation-reduction
8. If X represents an element that reacts with chlorine to form a compound with the
formula XCl2, what is the formula if X forms a compound with oxygen?
a. XO b. X2O3 c. X3O2 d. XO2
9. What is the unit for molar mass?
a. Mole
b. g/mol
c. grams
d. None of the above
10. Which is equivalent to -40° C?
a. -40° F b. 100° F c. 212° F d. 0° F
11. What is the symbol for the Nitride ion ?
a. N b. N+++ c. N2- d. N3-
12. What is the formula for the ammonia gas?
a. NH3 b. NH4Cl c. H2SO4 d. NH4OH
13. Which of the following salt is soluble in water?
a. Na2SO4 b. BaSO4 c. PbSO4 d. CaSO4
14. The correct name of Fe2O3 is
a. Iron Oxide b. Iron II oxide c. Iron III Oxide d. Iron monoxide
15. The formula for calcium sulfide is
a. Ca(SO4)2 b. CaSO4 c. Ca2SO4 d. CaS2
16. What is the mass of 1 mole of ammonia gas?
a. 14 g b. 17 g c. 23 g d. 18 g
17. If 6.3 mole of HCl and 2.8 mol of Ca(OH)2 is used in the following reaction. Which compound
will be the limiting reagent?
Ca(OH)2 + 2HCl à CaCl2 + H2O
a. HCl b. Ca(OH)2 c. H2O d. None
18. What is the formula mass of CaCO3?
a. 100.09 g/mol b. 100.09 amu c. 100.09 g d. None
19. What is the volume of 2 moles of O2 gas at STP?
a. 22.4 L b. 32.0 L c. 44.8 L d. None
20. 10 g of NaOH is dissolved in 250 ml of water. What will be the concentration of this solution?
a. 1 M b. 0.5 M c. 0.25 M d. 0.05 M
II. Write the chemical formula of the following compound. (15)
1. Calcium Hydroxide
2. Sodium phosphate
3. Aluminum oxide
4. Sulfuric acid
5. Silver nitrate
6. Sodium carbonate
7. Potassium permanganate
8. Magnesium phosphate
9. Manganese dioxide
10. Copper I oxide
Write the ions present in the following compounds and write their chemical name (15)
Formula Ions present Chemical name
1. CoCl2
2. Fe2O3
3. K2CrO4
4. Na2Cr2O7
5. Mg(OH) 2
6. Ag2SO4
7. HgO
8. SnCl4
9. Ca2P3
10. Na3PO4
III. Complete if necessary and balance the following chemical reactions and identify the type of reaction
occurred. (20)
a. K2SO4 + AgNO3 KNO3 + Ag2SO4
b. burning of magnesium in air
c. Fe + O2 Fe2O3
d. N2 + H2 à NH3
e. Ca(OH)2 + HCl à CaCl2 + H2O
f. NaOH + H2SO4 à Na2SO4 + H2O
g. H2 + O2 à H2O
h. Zn + HCl à ZnCl2 + H2
i. KClO3 à KCl + O2
j. CH4 + O2 à CO2 + H2O
IV. (A) A sample of urea contains 1.121g of N, 0.161g of H, 0.480g of C, and 0.640g of O. What is the empirical formula of urea? (15)
(B) Methane burns in the air by the following equation: (15)
CH4 + 2O2 à CO2 + 2H2O
What mass of water is produced by burning 500.0 g of methane ?