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5.1: From Particles to Solutions
Suggested Answers to Homework Questions
1. All matter is composed of tiny particles separated by empty spaces. Different
substances are made up of different types of particles. Particles are in constant,
random motion. Particles of a substance move faster as its temperature increases.
Particles are attracted to each other.
2. Heating water speeds up particles to gain enough thermal energy to break the
attractions between particles,
allowing them to slide past one another and form a liquid state.
3. Pure substances include water, sugar, and salt.
4. Mixtures include iced tea, concrete, and cereal.
5. A mechanical mixture is a mixture in which the individual components are still
distinguishable, such as pasta.
6. A solution is a mixture of materials combined together to form a homogenous
substance, such as sea water. The individual components are not distinguishable.
8. (a) A pane of clear glass is a solution.
(b) Chocolate chip ice cream is a mechanical mixture.
(c) Clear apple juice is a solution.
(d) A pizza is a mechanical mixture.
(e) Garbage in a garbage can is a mechanical mixture.
9. An alloy that is a soft, malleable material, that is liquid when heated but solidifies
quickly when cooled would make an effective solder material.
10. Lead is not used in solder because it is highly toxic and is prone to leaching at
higher temperatures.
CHEC
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5.2: Physical Properties
Suggested Answers to Homework Questions
1. A qualitative physical property provides non-measurable information about a
sample, such as its texture or taste.
A quantitative physical property measures the tangible properties of the sample, such
as its temperature, size
and mass.
2. (a) qualitative
(b) quantitative
(c) qualitative
(d) quantitative
3. Materials used to construct a mountain bike should be strong and lightweight.
4. (a) hard, shiny, copper coloured, conductive
(b) 500 g, yellow, greasy, malleable
(c) white, opaque, viscous, slightly sweet, liquid
(d) malleable, waxy, soft, cylindrical
(e) shiny, conductive, silver-coloured, malleable
(f) white, crystalline, sweet, soluble in water
(g) soft, viscous, white, adhesive/sticky
5. (a) The dimensions of the fabric change without altering its composition.
(b) The salad is a mixture of ingredients. It does not alter the composition of any one
ingredient.
(c) None of the components in the lawnmower had their original composition
changed. They were simply rearranged into a boat engine.
(d) Neither the water nor the salt crystals have undergone a change in their
composition during the evaporation process.
(e) Combining juice concentrate and water creates a mixture of the two substances
but does not alter the basic composition of either substance and does not produce a
new substance.
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5.3: Chemical Properties
Suggested Answers to Homework Questions
1. A chemical change is a process in which a substance or multiple substances are
chemically modifi ed to produce one or more entirely new substances. No new
substances are produced in a physical change.
2. Freezing water is only changing the state of state of the substance from a liquid to
a solid and does not produce any new substances.
3. (a) This is a physical property because lustre does not involve creating a new
substance.
(b) This is a physical property because it involves a change in state.
(c) This is a chemical property because a chemical reaction has triggered the
explosion and new substances are produced by the explosion.
(d) This is a chemical change because a chemical reaction is likely to have created
the change in colour.
4. (a) physical change
(b) physical change
(c) Chemical change. The reaction between the fi re and the wood produces new
substances, such as carbon dioxide and ash, and the process cannot be reversed.
(d) physical change
(e) Chemical change. There are colour changes, texture changes, and smells emitted
that all point toward a chemical change occurring.
5. The fact that the breaking of the glowstick causes the substance inside to emit
light and produces a change in
colour is strong evidence that a chemical change is taking place.
6. (a) The physical change I observed was the wax changing state from a solid to a
liquid as it is heated.
(b) The candle became shorter because the wax was being burned. There was a
chemical change that turned the wax into new substances, such as gases that
escaped into the air. The candle also became shorter because some of the wax near
the fl ame melted and dripped to the base of the candle where it re-solidifi ed.
(c) The emission of light and thermal energy, and wax changing into gas, indicates
that a chemical change is taking place.
7. (a) A chemical change is occurring as the motor ignites, as evidenced by the
exhaust gases produced.
(b) A chemical change is occurring because the chemical forming the stain undergoes
a change in composition, as evidenced by a colour change.
(c) A chemical change is occurring as shown by the gas bubbles produced.
(d) The baking process is causing the ingredients within the cookies to be chemically
altered, as evidenced by the change in colour and a smell (gas) being emitted.
(e) A chemical change is occurring as the chemicals in the match ignite, producing
thermal energy and light are emitted and gas is produced.
(f) The bleach reacts with the dye causing it to change colour.
(g) The darker colour of the banana suggests that the ripening process is a chemical
change. In fact, as bananas ripen, starches are converted to sugars, making ripe
bananas sweet.
5.6: Characteristic Physical Properties
Suggested Answers to Homework Questions
1. The boiling point of water is a characteristic physical property because it is a
property that is unique to water. The temperature and volume of the glass of water
have nothing to do with its physical makeup and can be applied to virtually any kind
of viscous liquid.
2. Mercury conducts electricity and is liquid at room temperature, making it ideal for
use in a thermostat.
3. Unlike water, liquid silver is less dense then solid silver. This would cause the
denser silver cube to sink.
4. Its volume is 0.635 cm3.
5. The metal is copper, which has a density of 8.96 g/cm3.
6. Its mass is 33.6 g.
7. The metal is aluminum, which has a density of 2.70 g/cm3.
8. Its volume is .631 cm3.
9. The metal is lead, which has a density of 11.36 g/cm3.
10. 14 252.76972 g 5 14 300 g
11. (a) Water is said to exhibit unusual behavior because it is less dense in a solid
state than it is in a liquid state.
(b) The unusual behaviour of water leads to the phenomenon of ice fl oating on the
top of lakes and oceans. This is also the reason why a glass bottle fi lled with a
beverage will crack after being placed in the freezer, as the distance between water
particles expands when the water freezes. This phenomenon can also cause pipes to
burst as temperatures drop and water expands within the pipes.
12. Find the mass of a measured volume of the liquid and calculate its density.
Thevaluefordensitywillbecloseto1g/mL for water and 0.79 g/mL for alcohol.