CHAPTER 1- Chemistry: The Study of Change DR. PAHLAVAN
1. Classify the following as a pure substance (element-compound) or a mixture (homogeneous-heterogeneous). a) air b) a nickel c) magnesium d) lotion d) salad dressing 2. Perform the following conversions: a) 0.0025 mm to nm b) 0.88 pm to cm c) 2.50x10-6 kg/L to mg/ ml 3. A cubic piece of a nickel metal measures 5.25 cm on each edge. If the density is 8.9 g/cm3, what is the mass of the cube? 4. Determine the number of significant figures in each of the following measured quantities? a) 0.000289 m b) 3.50x108 g c) 202.040 cm d) 8.089 L 5. Perform the following calculations and round off the answer to the proper significant figures: a) 1.25 m + 6.2 m – 8.01 m + 0.899 m = ______
b) 78.8680 g/ (23.5ml + 10 ml) = ______6. An automobile is able to travel 900 mi on 35.8 gal of gasoline, what is the gas mileage in km/L?
7. Neon has a low boiling point of approximately –246 oC. What is the boiling point in Kelvins and oF?
8. Round off the following to three significant figures: a) 134.89 m b) 80 g c) 1255 ml d) 1.2x10-5 mm
9. A balance has a precision of +/- 0.001g. A sample weighs about 8 g on this balance. How many significant figures should be reported for this measurement?
10. The density of a metal is 9.80 g/ml. What is the mass of a sample of metal when dropped in28.9 ml water, the volume increases to 56.4 ml?
11. Label each of the following as either a physical process (change) or a chemical process (change). a) The metal gets warmer b) Explosion of nitroglycerin c) Corrosion of Iron metal d) Water condenses on the metal
12. Identify the following characteristics as physical properties or chemical properties.
a) Silver metal is white b) Zinc has a density of 7.13 g/ml at 25 0C c) Silver is a lustrous metal d) Sodium is highly reactive with water CHAPTER 1- Chemistry: The Study of Change (answers) DR. PAHLAVAN
1. Classify the following as a pure substance(ps) (element-compound) or a mixture(m) (homogeneous-heterogeneous).
a) air (m –homogeneous , solution) b) a nickel (m) c) magnesium (ps)
d) lotion (m –homogeneous) d) salad dressing (m –heterogeneous)
2. Perform the following conversions: a) 0.0025 mm to nm (0.0025mm)(1m/1000mm)(109 nm/1m) = 2500nm b) 0.88 pm to cm (0.88pm)(1m/ 1012 pm)(100cm/1m) = 8.8 x10 -11 cm c) 2.50x10-6 kg/L to mg/ ml
(2.50 x10-6kg/L)(1000g/1kg)(1000mg/1g)(1L/1000ml) = 2.5 x 10 -3 mg/ml
3. A cubic piece of a nickel metal measures 5.25 cm on each edge. If the density is 8.9 g/cm3, what is the mass of the cube?
Mass = D.V. = (5.25cm)3 x 8.9 g/cm3 = 1287.9 g
4. Determine the number of significant figures in each of the following measured quantities?
a) 0.000289 m (3) b) 3.50x108 g (3) c) 202.040 cm (6) d) 8.089 L (4)
5. Perform the following calculations and round off the answer to the proper significant figures:
a) 1.25 m + 6.2 m – 8.01 m + 0.899 m = 0.3m
b) 78.8680 g/ (23.5ml + 10 ml) = 2.35g/ml
6. An automobile is able to travel 900 mi on 35.8 gal of gasoline, what is the gas mileage in km/L?
(900 mi/35.8 gal)(1.61 km/1 mi)(1 gal/ 4qts)(1.06qts/1 L) = 10.7 km/ L 7. Neon has a low boiling point of approximately –246 oC. What is the boiling point in Kelvins and oF? K = oC + 273 = -246 + 273 = 27 K
oF = (9/5)(-246) + 32 = -410.8 oF
8. Round off the following to three significant figures: a) 134.89 m = 135 m b) 80 g = 80.0 g c) 1255 ml = 1.26 x 103 ml
d) 1.2x10-5 mm = 1.20 x10-5 mm
9. A balance has a precision of +/- 0.001g. A sample weighs about 8 g on this balance. How many significant figures should be reported for this measurement?
8.000 g 4 sig. fig.
10. The density of a metal is 9.80 g/ml. What is the mass of a sample of metal when dropped in28.9 ml water, the volume increases to 56.4 ml?
Mass = D.V = (9.80g/ml)(56.4ml – 28.9ml) = 2.70 x 10 2 g
11. Label each of the following as either a physical process (change) or a chemical process (change).
a) The metal gets warmer (physical) b) Explosion of nitroglycerin (chemical) c) Corrosion of Iron metal (chemical) d) Water condenses on the metal (physical)
12. Identify the following characteristics as physical properties or chemical properties.
a) Silver metal is white (physical) b) Zinc has a density of 7.13g/ml at 25 0C (physical) c) Silver is a lustrous metal (physical) d) Sodium is highly reactive with water (chemical)