Answers to Ch 2, 3 Assessment Questions
Page 58 Chapter 2 assessment
35. Intensive properties do not depend on mass. They are properties of the material e.g. density, color, etc.
Extensive properties depend on mass. They are properties of an object or a given amount of substance e.g. mass, volume, etc.
40. A vapor. A vapor is the gaseous state of a substance that is solid or liquid at room temperature
45. A phase is any part of the sample with uniform composition and properties. See page 45. A solution is a perfect mixture i.e. thoroughly mixed even at a molecular scale. Therefore it has uniform composition and properties and is ONE PHASE.
50. A) NH3 = nitrogen, hydrogen.
B) K2O = potassium, oxygen.
C) C12H22O11 = carbon, hydrogen, oxygen.
D) CaS = calcium, sulfur.
55. Physical properties can be observed without changing the composition of the substance.
60. Ethanol is a colorless liquid at -30° C since that is above its melting point but below its boiling point.
65. Difficult question! I think the best answer in both locations is 'mixtures' since mixtures include paints, clouds, blue sky, tree bark, leaves, stainless steel pans etc etc
70) (After looking up the melting points on the Internet)
Gallium freezes first at 30° C
Water freezes next at 0° C
Mercury freezes last at -39° C
80) Assuming 'abundant' means 1.4% or more,
A) oxygen, calcium
B) silicon, iron, aluminum
C) different, since the only compound that can be formed with elements that are abundant in both the body and the earth's crust is calcium oxide, but the body must contain many other compounds in abundance.
Page 96 Chapter 3 Assessment
60) A) Round to 0 decimal place: 43 g
B) Round to 1 decimal place: 225.6 L
C) Round to three significant figures: 92.0 kg
D) Round to three significant figures: 32.4 m3
65) You can't do these since no physical textbook yet!
A) 5.9 mm
B) 14.30 cm
C) 21.4 cm
70) A) 157 cs = 1.57 s
B) 42.7 L x (1000mL/1L) = 42700 mL
C) 261 nm x (1mm/1 000 000 nm) = 0.000 261 mm
D) 0.065 km x (10 000 dm / 1 km) = 650 dm
E) 642 cg x (1 kg / 100 000 cg) = 0.006 42 kg
F) 825 cg x (10 000 000 ng / 1 cg) = 8 250 000 000 ng = 8.25 x 10^9 ng
75) Yes, the person would have the same mass and volume and therefore the same density.
80) A) high accuracy and precision.
B) High precision, not so accurate.
C) Poor precision and poor accuracy.
85) According to the table on page 90, the density of ethanol = 0.789 g/cm3 and the density of gasoline = 0.66-0.69 g/cm3.
I think this question is incorrect since it is not possible for a material to have a density which is greater than 0.789 g/cm3 AND less than 0.69 g/cm3.
A) C2: -100, C4: 0, C6: 68, C8: 125
C) 350 K = 350-273 °C = 77° C so C1-C6
D) Taking first and last, 151 - -162 = 313 °C increase when add eight carbons so 313/8 = 39.1°C per carbon atom added.
95) Yes, an astronaut on her way to the moon would lose weight as she moves away from Earth but her mass would not change.
100) There are different types of gasoline (a mixture of different hydrocarbons) with different densities.
105) Air density = 1.2 g/L = 1.2 kg/m3
D=m/V m= DV = 1.2 kg/m3 x (25.0 m x 15.0 m x 4.0 m) = 1800 kg.