Practice ProblemsChang, Chapter 1

Chemistry: The Study of Change

1.7 Measurement

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• A piece of platinum metal with a density of 21.5 g/cm3 has a volume of 4.49 cm3. What is its mass?

Answer: 96.5 g

1.7 Measurement

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• The density of sulfuric acid in a certain car battery is 1.41 g/ml. Calculate the mass of 242 mL of the liquid.

Answer: 341 g

6.4 Enthalpy of Chemical Reactions

• Convert:a) 327.5°C (the melting point of lead) to degrees Fahrenheit;b) 172.9°F (the boiling point of ethanol) to degrees Celsius;c) 77 K, the boiling point of liquid nitrogen, to degrees Celsius.

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Answers: a) 621.5°F b) 78.3°C c) -196°C

1.8 Handling Numbers

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• Determine the number of significant figures in each of the following measurementsa) 24 mLb) 3001 gc) 0.0320 m3

d) 6.4 x 104 moleculese) 560 kg

Answer: a) 2b) 4c) 3d) 2e) 2

1.8 Handling Numbers

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• Carry out the following arithmetic operations & round off the answers to the appropriate number of significant figures:a) 26.5862 L + 0.17 Lb) 9.1 g – 4.682 gc) 7.1 x 104 dm x 2.2654 x 102 dmd) 6.54 g ÷ 86.5542 mLe) (7.55 x 104 m) – ( 8.62 x 103 m)

Answers: a) 26.76 Lb) 4.4 gc) 1.6 x 107 dm2

d) 0.0756 g/mLe) 6.69 x 104 m

1.9 Dimensional Analysis in Solving Problems

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• A roll of aluminum foil has a mass of 1.07 kg. What is its mass in pounds?

Answer: 2.36 lb.

1.9 Dimensional Analysis in Solving Problems

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• The volume of a room is 1.08 x 108 dm3. What is the volume in m3?

Answer:1.08 x 105 m3

1.9 Dimensional Analysis in Solving Problems

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• The density of the lightest metal, lithium (Li), is 5.34 x 102 kg/m3. Convert the density to g/cm3.

Answer: 0.534 g/cm³