SNC1D
Particle Theory and Classification Worksheet
Name: _Anne Sirs_
QUESTIONS
1. What is temperature?
Temperature is a measure of the average speed of the particles in a substance (hot = high temp,
cold = low temp).
2. Sound travels as a wave. Why does it travel faster in water than in air?
Sound waves travel by neighbouring particles bumping into one another to pass along the energy.
Because neighbouring particles are closer in a liquid than in a gas, the water particles don’t need to
travel as far as air particles do to pass the sound energy along.
3. Use the Particle Theory and your understanding of density to explain why a hot air balloon rises
when it is heated.
When air gets heated the particles move faster and get farther apart. Therefore a balloon full of
hot air would have fewer particles in a given amount of space than the air around it (i.e. hot air is less
dense than cooler air). Because less dense materials “float” on top of more dense materials, the
balloon floats in/on the surrounding air.
4. As spring approaches, drivers are encouraged to let air out of their tires. Why do they do this?
The warmer temperatures of springtime cause the air particles inside the tires to move faster and
spread out more. This means that the tires become “overinflated” and will pop more easily if they hit
a pothole, so by letting some of the warmer air out of the tires they will be inflated to the same level
as when they had more air in there during the cooler months.
5. Explain why the handle of a spoon gets hot when it is placed in a cup of boiling water.
The fast-moving particles of the hot water bump into the particles in the immersed part of the spoon
and transfer some of their energy to the spoon particles making them move faster (i.e. heat up).
These particles then bump into their neighbouring particles in handle of the spoon making them move
faster and heat up too.
6. Classify each of the following as a solution, heterogeneous mixture, element or compound.
a)
b)
c)
d)
e)
oxygen gas compound
smoke in air solution
Italian salad dressing heterogeneous mixture
Soda pop (with bubbles) het. mix.
Copper wire element
f) carbon dioxide compound
g) sodium chloride (salt) compound
h) air mixture
i) ammonium nitrate compound
j) sodium bicarbonate (baking soda)compound
7. What is the difference between an atom and a molecule?
An atom is a single particle that is the smallest unit of an element, whereas a molecule is a larger
particle that is a collection of two or more atoms bonded together.
8. The chemical formula for table sugar is C12H22O11 .
a) Explain why sugar is considered a compound.
According to this formula, each molecule of sugar contains 12 carbon atoms, 22 hydrogen atoms, and
11 oxygen atoms – this is a compound because it is a combination of different elements.
b) Explain why it is considered a pure substance.
Sugar is a pure substance because each of its particles are identical. If you were to use the world’s
tiniest tweezers and repeatedly pull one particle off of a single grain of sugar, every time it would be
a C12H22O11 particle.