CHM 1045 Spring 2015
Test 2
Name (print)___________________
Show your work for complete (and partial) credit. Report your answers to the correct
number of significant figures, and use units where appropriate. All chemical equations
should balance; indicate phases.
What are the formulas for the following compounds?
1. sodium sulfide
calcium sulfate
2. iron(II)hydroxide
sulfur trioxide
What are the names of the following compounds?
3. CuO
NO
4. Zn(NO2)2
LiClO2
5. a) What information is present in a structural formula that is not present in a
molecular formula?
b) What information is present in a molecular model that is not present in a structural
formula?
6. How is an empirical formula for a molecular compound similar to the formula unit for
an ionic compound?
7. What is the mass percentage of nitrogen in (NH4)2S?
The following information applies to the next two problems.
Compound: MgCl2
Mg(NO3)2 AgCl
AgNO3
f.w.(g/mol): 95.211
148.435
143.321
169.87
MgCl2(aq) + 2AgNO3(aq) → 2AgCl(s) + Mg(NO3)2(aq)
8. How many mols of AgNO3 are required to form 0.275mol of AgCl?
9. What mass of MgCl2 is required to form 1.223g of AgCl?
10. A 23mg sample of a hydrocarbon (a compound composed only of carbon and
hydrogen) was burned in excess oxygen, yielding 70.mg of carbon dioxide (CO2,
44.01g/mol) and 36mg of water (H2O, 18.015g/mol). What is the empirical formula
for the compound?
11. What is the theoretical yield (in grams) of the product, Al2O3 (101.962g/mol) when
15.0g of each reactant is allowed to react by the following equation? NOTE: this is a
limiting reactant problem. 4Al(s) + 3O2(g) → 2Al2O3(s)
12. Write the net ionic equation for the following reaction.
Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g)
13. Indicate whether the following reactions are precipitation, acid/base, or
oxidation/reduction reactions. Check the appropriate boxes.
Reaction
precip.
2C2H6(g) + 7O2(g)  4CO2(g) + 6H2O(l)
2AgNO3(aq) + Cu(s)  Ag(s) + Cu(NO3)2(aq)
H2SO4(aq) + Zn(s)  ZnSO4(aq) + H2(g)
H2SO4(aq) + Na2CO3(aq)  CO2(g) + H2O(l) + Na2SO4(aq)
H2SO4(aq) + BaCl2(aq)  BaSO4(s) + 2HCl(aq)
a/b
14. a) In the reaction, Mg(s) + Cl2(g)  MgCl2(s), what is the oxidizing agent?
b) In the net ionic reaction Cu(s) + 2Ag+(aq)  Cu+2(aq) + 2Ag(s),
____ is oxidized to ____ and ____ is reduced to ____.
15. Predict the products of the following reaction.
Mg(OH)2(aq) + H2S2O3(aq) →
16. Provide the oxidation number of each of the underlined species.
ox/red
a) ZnCl2
b) K2SO4
c) MnO4-
d) NH4+
e) Br2
17. Aqueous solutions of barium nitrate and sodium sulfate were mixed. A sulfate
compound precipitated. Write a net ionic equation for the reaction that occurred.
18. How many mols of Na2C2O4 (134.0g/mol) are in 125.0mL of .0233M Na2C2O4?
19. In the reaction 2AgNO3(aq) + Cu(s)  2Ag(s) + Cu(NO3)2(aq), what volume of
1.88M 2AgNO3(aq) (169.9g/mol) would completely react 20.0g Cu(s)?
20. In the titration of a 25.00mL sample of HCl(aq), 19.44mL of .123M NaOH titrant was
required to reach the endpoint. What was the concentration of the HCl sample?
6 points extra credit:
What are the names and formulas of the three strong acids commonly found in
laboratories?