# Midterm #1 - Seattle Central College

```1. Convert 6.114 x 10-16 km2 to cm2.
2. Para-cresol (p-cresol) is used as a disinfectant and in the manufacture of herbicides. A 0.3654 g
sample of this carbon, hydrogen, oxygen, compound yields 1.0420 g CO2 and 0.2437 g H2O in
combustion analysis. Its molar mass is 108.0 g/mole.
a. Determine the mass percent composition
b. Determine the empirical formula
c. Determine the molecular formula.
3. What does the atomic number tell us about an element?
4. What does the mass number describe about an isotope?
5. When an element is oxidized
a. What happens to its oxidation number? (increase, decrease, or stay the same)?
b. During this oxidation process are electrons lost or gained?
6. How many atoms of fluorine are contained in a 1.00 g sample of iodine heptafluoride?
7. In the germination reaction of glucose (C6H12O6, MW = 180.16 g/mole)
C6H12O6 → 2 C2H5OH + 2 CO2
10.0 g of glucose is reacted with excess yeast to produce 2.52 g of ethanol (C2H5OH). What is the
percent yield of ethanol?
8. Balance the following equations:
a.
IBr
+ NH3
→
NI3
+
NH4Br
b. The complete combustion of thiophene C4H4S.
c. Heat decomposes phosphorous acid to phosphoric acid and phosphine (PH3).
9. The reaction 2NaIO3 + 5 NaHSO3 → 3 NaHSO4 + 2 Na2SO4 + H2O + I2
can be used to make iodine. If 20.0 g of NaIO3 reacts with 25.0 g of NaHSO3, what mass of I2 is
formed and what is the mass of the excess reactant?
10. List the five driving forces that can be used to determine if a set of reactants will produce products.
11. Give names for the following formulas:
Name the Following
Give Formulas
a. Au2S3
a. Hypochlorus acid
b. Mn2O7
b. SO3
c. S4N2
c. Hydrogen oxide
d. HCN (aq)
d. Chromium(VI) oxide
e. HCl (g)
e. Carbon tetrachloride
f. H2S (aq)
f. Zinc acetate
12. Balance the following REDOX equation by the oxidation number method. Also, identify the
oxidizing and reducing agent.
HNO3 + Cu2O → Cu(NO3)2
+ NO + H2O (acidic)
13. Give units for the following:
a. Mass
b. Density
c. Molar mass
d. Concentration
14. A 50.0 mL aliquot of 0.1000 M Ba(NO3)2 is combined with 25.00 mL of 0.2040 M sodium sulfate
solution.
a. Using the solubility rules on the Periodic Chart to write and balance the formula equation,
ionic equation and the net ionic equation. If there is no net ionic equation write NR
b. Find the mass of BaSO4 produced
c. Find the concentrations of all ions present in the aqueous mixture after the reaction is
complete.
15. Balance the following REDOX equation by the half reaction method.
22+
C2O4 + MnO4
→ Mn
+ CO2
```