CHM 1045 Fall, 2014
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.
NA = 6.022 x 1023
1. What are the formulas for the following compounds?
a) sodium sulfate
b) calcium sulfide
c) aluminum oxide
2. What are the names of the following compounds?
a) CuCl2
b) Ba(NO2)2
c) NO2
3. The formula for calcium oxalate is CaC2O4. What is the formula for sodium oxalate?
4. What is the mass of 1.33mol of C2H6?
5. How many moles of water (H2O, 18.015g/mol) is 2.5 x 104g of water?
6. What mass of CaCl2 (110.99g/mol) contains 8.50g of chlorine?
The following information applies to the next five 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)
7. How much does 0.055mol of magnesium chloride weigh?
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. What volume of 0.100M MgCl2 contains 0.955g of MgCl2?
11. What volume of 0.100M AgNO3(aq) is required to react with 247mL of 0.100M
MgCl2(aq)?
12. In an elemental analysis experiment, a compound containing only carbon and
hydrogen was combusted. The combustion products were analyzed and found to
contain two moles of CO2 for every 3 moles of H2O. What was the empirical formula
for the compound?
13. What is the empirical formula of a compound that is 41.78% sodium, 29.14% sulfur,
and 29.08% oxygen, by mass?
14. In the following reaction, if 15.0g of each reactant is allowed to react, what will be
the theoretical yield of the product, Al2O3 (101.96g/mol), in grams? Note: this is a
limiting reactant problem. 4Al + 3O2 → 2Al2O3.
15. Write a balanced net ionic equation for the following equation.
H2SO4(aq) + Mg(s)  MgSO4(aq) + H2(g).
16. Write a net ionic equation for the reaction described. Mixing solutions of sodium
sulfide and silver nitrate (AgNO3) causes a silver sulfide precipitate.
17. Predict the products of the following reactions; balance the equations and include
phases.
___C2H6(g) + ___O2(g) →
___Ca(OH)2(aq) + ___HNO3(aq) →
18. Provide the oxidation number of each of the underlined species.
a) MnO4b) H2SO4
c) ZnCl2
d) NH4+
e) Cl2
19. Write the oxidation half reaction for the reaction 2Mg(s) + O2(g) → 2MgO
20. Mg(NO3)2(aq) + Na2CO3(aq) → MgCO3(s) + 2NaNO3(aq)
What can you say about the solubility of the four compounds in the reaction? For
each compound, check the appropriate box.
Compound
Soluble
Insoluble
Not enough information to decide.
Mg(NO3)2
Na2CO3
MgCO3
NaNO3
5 points extra credit: A 25.00mL sample of Ca(OH)2(aq) was titrated using .1800M HCl,
requiring 39.55mL of HCl to reach the endpoint. What was the concentration of the
Ca(OH)2?