Gr.9 Science

Question 1

Define a pure substance and a mixture, then give an example for each.

Answer 1

Pure substance: A substance made from one atom, molecule, or compound (ex: Helium)

Mixture: made of two or more particles that are not chemically combined (ex: Chocolate Milk)

Question 2

Define Adhesion and Cohesion, then give an example for each.

Answer 2

Adhesion: A property that makes a substance stick to others (ex: Tape)

Cohesion: A property that makes something stick to itself (ex: Mercury)

Question 3

Define a Chemical Change and a Physical Change, and give an example for each.

Answer 3

Chemical Change: A reaction that results in the production of new substances (ex: Rusting of metal)

Physical Change: Alters the form or appearance without changing chemical composition (ex: Making Chocolate Milk)

Question 4

Define Density and Mass and give an example for each.

Answer 4

Density: How much Mass is in a certain Volume (ex: Pool Noodles have a small density)

Mass: The amount of Matter in an object (ex: My mass is 59kg)

Question 5

What are the charges and masses of the 3 subatomic particles? (proton, neutron, electron)

Answer 5

Proton charge: +1
Proton mass: 1836

Neutron charge: 0
Neutron mass: 1837

Electron charge: -1
Electron mass: 1

Question 6

Define the two categories of pure substances (Elements, Compounds) and give an example for each.

Answer 6

Element: Contains one particle (ex: Oxygen)
Compounds: 2 or more chemically combined Elements (ex: Water (H20))

Question 7

Define Homogenous and Heterogenous mixtures, and give an example of each.

Answer 7

Homogeneous: Parts of mixture look the same (ex: Chocolate Milk)

Heterogeneous: Parts of mixture look different (ex: Chocolate Chip Cookie Dough)

Question 8

Give the equations to find Density, Volume, and Mass.

Answer 8

Density: D=m/V
Volume: V=m/D
Mass: m=DxV