Unit 2 - Chemistry

Question 1

What is a pure substance?

Answer 1

A substance that is the same throughout the sample. For example, a bowl full of table salt (Sodium chloride) is a pure substance, but as soon as you mix something else with it, its a mixture/compound.

Question 2

What is the difference between physical and chemical changes?

Answer 2

Physical changes are temporary and can be reversed, but chemical changes cannot be reversed.
EXAMPLES: Water freezing is a physical change. Popcorn popping is a chemical change.

Question 3

When a solid changed to a gas, it is called _________.

Answer 3

Sublimation

Question 4

Neutrons have ______ charge.
Electrons have a _______ charge.
Protons have a ______ charge.

Answer 4

No charge
Negative
Positive

Question 5

Where are each of these particles located within the atom?
Protons
Neutrons
Electrons

Answer 5

Protons are inside the nucleus of the atom.
So are the neutrons.
Electrons orbit the nucleus of the atom.

Question 6

What are some properties of chemicals?

Answer 6

Is/does it...
Radioactive
Flammable
Produce gas
Change colour
Conduct heat
etc...

Question 7

The elements to the far right of the periodic table are called…?

Answer 7

Noble gases

Question 8

The elements to the far left of the periodic table are called…?

Answer 8

Alkali Metals

Question 9

The elements to the right of the alkali metals are called…?

Answer 9

Alkaline earth metals

Question 10

The elements in the middle of the periodic table are called…?

Answer 10

Transition metals

Question 11

What are qualitative and quantitative properties of stuff?

Answer 11

Qualitative properties deal with descriptions that cannot be measured.
EXAMPLES: Colour, texture, smell, taste…

Quantitative properties deal with numbers and things that can be measured.
EXAMPLES: Length, area, volume, height…

Question 12

How would you draw a BR (Bohr-Rutherford) diagram model of an oxygen atom?
Hint: Oxygen has an atomic number of 8 and has an atomic mass of 16

Answer 12

The atomic number tells you how many electrons there are, AND how many protons are in the nucleus.
Since you know there are 8 protons, you would subtract that number from the atomic mass to find the number of neutrons. In this case:
16 - 8 = 8 neutrons in the nucleus

To draw the diagram, you would write the number of protons and neutrons in the nucleus as this:
P 8
N 8
Then, draw the electrons orbiting the nucleus. The first shell has 2, the second one has 8, third has 8, and so on.

Question 13

What are the rules for drawing the electrons in their shells on BR diagrams?

Answer 13

The first shell always contains only 2 electrons. They are both at the top.
The second shell has 8, and they go NORTH, SOUTH, EAST, then WEST.
+The third shell has the same rules as the second one, and so on.

Question 14

How many protons, neutrons, and electrons does the following element have:
Silicon (Si)
A# - 14
AM - 28

Answer 14

Electrons - 14
Protons - 14
Neutrons - AM - A#
28 - 14
= 14

Question 15

How many protons, neutrons, and electrons does the following element have:
Bromine (Br)
A# - 35
AM - 80

Answer 15

Electrons - 35
Protons - 35
Neutrons - AM - A#
80 - 35
= 45

Question 16

What is the difference between a heterogenous and homogenous mixture?

Answer 16

A heterogenous mixture is a mixture in which you can see the different substances, while in a homogenous mixture you cannot identify the different substance by sight.

Question 17

What is the difference between a suspension and solution?

Answer 17

A solution is a complete mixture of two compounds, and a suspension is tiny particles of one compound inside another.

Question 18

Mixture can be separated by?

Answer 18

physical and mechanical methods.

Question 19

What is the difference between a pure substance and a mixture?

Answer 19

A pure substance has a constant composition.

Question 20

What are the two categories of pure substance?

Answer 20

Elements and compounds.

Question 21

What is the difference between an element and a compound?

Answer 21

An element is one kind of atom, and cannot be broken down into further particles. A compound is two or more types of atom, and is always the same ratio.

Question 22

What is the particle theory of matter?

Answer 22

The theory that everything is made up of small particles, called atoms.

Question 23

What are physical properties?

Answer 23

Properties that can be identified without changing a substance’s composition.

Question 24

What are chemical properties?

Answer 24

Properties that have to do with reactions, such as:
Reaction with water
Reaction with oxygen
Reaction with acid
Toxic (reacts with organism)
Radioactive (nuclear reaction)
Combustible

Question 25

What are some physical properties of matter?

Answer 25

Color
Texture
Odour
Lustre (shiny-dull)
Clarity (opaque-transparent)
Taste
State of matter
Melting and boiling points
Crystal form (texture -> powder, definite shape)
Viscosity
Hardness (Resistance)
pH (Acidic-Basic)

Question 26

The safety symbol shapes mean?

Answer 26

Octagon - danger
Diamond - warning
Triangle - caution

Question 27

All hazardous products must have labels. The information on the product can be found on the?

Answer 27

MSDS, or Material Safety Data Sheet.

Question 28

What are the WHMIS symbols?

Answer 28

Compressed gas (bottle)
Flammable (flame)
Oxidizer (fire on circle)
Poisonous (skull/crossbones)
Toxic (Capital T)
Biohazard (circles)
Corrosive (burning drip on hand and table)
Reactive (Capital R with test tube)