**AP Chemistry BOZEMAN #2 Chemical Analysis Name:**

**15 points**

1. CH

_{2}O is the empirical formula of what molecule?
2. What is the molar mass of gold (give a unit!)?

3. Notice
that even though hydrogen and oxygen are diatomics, when dividing by the

mass
of each element to find moles, you only use 1 gram and 16 grams respectively. What are the three steps in finding the
empirical formula when given a mass
spectrum analysis?

a)

b)

c)

4.

**SHOW WORK FOR POINTS IN THIS PROBLEM.**(10 points)
Nicotine is composed of
C,H, and N. A 5.250 mg sample of
nicotine was combusted, producing 14.242 mg of CO

_{2}and 4.083 mg of H_{2}O. SIG FIGS COUNT!!!__HINT:__Don't worry about the mg - make them all grams. It's all about the ratio, baby.

a) What is
the mass of CO

_{2}?
b) FInd the
grams of carbon in the 14.242 g of CO

_{2}that is given:
c) Change
grams of C to grams to mols of C:

d) What is
the mass of H

_{2}O?
e) FInd the
grams of hydrogen in the 4.083 g of H

_{2}O that is given:
f) Change
grams of H to mols of H:

g) All that is left is finding the
nitrogen. To do this, subtract the
masses you got for the carbon (answer b)
and the hydrogen (answer e) from the total number of grams in the nicotine (given in the
problem). This is your grams of
nitrogen.

h) Convert your grams of nitrogen to moles of
nitrogen.

i) Divide
by the smallest number of mols to find the mol ratio. Show your work here:

j) What is the empirical formula for nicotine?

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