Example First Day Test
Key
1. Name these chemicals:
a. HCl     hydrochloric acid
b. H2SO4     sulfuric acid
c. HNO2     Nitrous acid
d. Ba(OH)2     barium hydroxide
e. SnO2     Tin(IV) oxide
f. NO2  Nitrogen dioxide

2. Write the formula of these chemicals:
a. Disulfur pentoxide      S2O5
b. Tin (II) selenate      SnSeO4
c. Iron (II) thiocyanate     Fe(SCN)2
d. Phosphoric acid     H3PO4

3. Is ammonium carbonate soluble or insoluble in water?
Soluble
4. Convert 2 ng to grams.
2 x 10-9 g
5. DDT (C14H9Cl5), an insecticide harmful to fish, birds, and humans can be produced by reacting chlorobenzene (C6H5Cl) with chloral (C2HOCl3).  The unbalanced chemical equation is:
 
If 922 grams chlorobenzene react with 477 grams chloral, determine:
a. The limiting reactant.
First, balance the equation:
2C6H5Cl + C2HOCl3 --> C14H9Cl5 + H2O
Calculate moles of each reactant:

Calculate how much of one reactant you need using the mole ratio from the equation:

We only have 3.24 mol C2HOCl3, so C2HOCl3 is the limiting reactant

b. The theoretical yield of DDT in grams.

c. The percent yield of DDT, if the actual yield of DDT is 198.0 grams.