Answers to Page 120 Problems 7, 8 & 9!

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Answers to Page 120
Problems 7, 8 & 9!
7. How many moles of H atoms are
there in 2.0 moles of C2H6O
molecules? Explain.
12 moles
In 1 mole of C2H6O molecule there would be 6
moles of hydrogen atoms. In 2 moles, 2 x 6 =
12 moles of Hydrogen atoms.
8. Which of these has the most moles
of lead atoms? Show your work and
explain your answer.
a. 1.0 grams of PbCl2
1 g = 0.0036 mol
Molar mass: 207.2 + 2(35.45) 278.1 g
= 278.1 g/mol
mol
b. 1.0 grams of PbCl4
1
g
=
0.0029
mol
Molar mass: 207.2 +
g
349
4(35.45) = 349 g/mol
mol
c. 1.0 grams of PbCO3
1 g = 0.0037 mol
Molar mass: 207.2 + 12.01
267.2 g
+ 3(16) = 267.2 g/mol
mol
9. Which has more moles of oxygen
atoms, 153 g of BaO or 169 g of BaO2?
Show your work!
Molar mass BaO: 137.33 + 16 = 153.33 g/mol
1 mole
153 g = 1 mol BaO
Oxygen
153.33 g
atoms
mol
Molar mass BaO2: 137.33 + 2(16) = 169.33 g/mol
169 g = 1 mol BaO2
169.33 g
mol
2 moles
Oxygen
atoms

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