Physical Science - Chapter 2 Review

Vocabulary

100

Another word for a homogenous mixtures

Solution

200

Fluids resistance to flow

Viscosity

300

The amount of space a sample of matter occupies.

Volume

400

The mass per unit volume of a substance. 

Density

500

How could you separate a homogeneous mixture that contains 2 liquids with different boiling points?

distillation

Chemical and Physical Changes

100

Explain the difference between chemical and physical changes.

Chemical changes: Two substances combine to create a new substance with different properties. Physical changes: Two substances are combined and each retains the same properties as the elements that make it up.

200

List 3 different evidences of a chemical change.

Change in color, production of odor, change in energy (absorbing heat or releasing heat, sound or light), formation of a gas, or formation of a precipitate.

300

List four physical properties of matter.

physical properties of matter: color, shape, size, state, melting point, freezing point, boiling point, malleability (the ability to bend), density, volume, mass, or solubility (the ability to dissolve)

400

Changes of state are considered which type of change? Explain why.

Changes of state are PHYSICAL changes because the substance still has the same chemical properties, just in a different form. Water is still water (H2O) when it is a liquid, solid (ice), or gas (water vapor).

500

Why are chemical properties harder to observe than physical properties?

Chemical properties change the substances identity or makeup.

Elements, Compound, and Mixtures

100

Define element

Element: a pure substance that is composed of only one type of atom. It cannot be broken down into simpler substances.

200

How can a compound be broken down? 

By a chemical reaction. 

300

What is a diatomic element? 

An element in its pure from that bonds with itself. 

400

How is a compound different from a mixture?

Mixtures DO NOT combine in a specific ratio, they are physically combined and can be separated, the elements in the mixture keep their physical properties, and they do not form a new substance.

500

Why are compounds considered to be a pure substance?

It is a pure substance because compounds are composed of only one type of particle and the particles are chemically combined. Also different samples of any compound have the same elements in the same proportion. For example water is always composed of 2 hydrogen molecules and 1 oxygen molecule.

Solutions, Suspensions, and Colloids

100

What is a solution.

A solution is a homogeneous mixture of a solvent and a solute. The solute is the substance that is dissolved and the solvent is the substance that the solute is dissolved into. For example in a solution of salt water the salt is the solute and the water is the solvent.

200

Compare and contrast heterogeneous and homogenous mixtures.

Homogenous mixtures are the same throughout. You can take a sample from any part of the mixture and it will have the same composition. Heterogeneous mixtures are different throughout. They may have clumps or large concentrations of different elements throughout a sample. They are similar because they are both mixtures and are made of one or more substance that is physically combined.

300

True of False: Salt water is a homogeneous mixture

True

400

A student stirred some sand into a container of water and left the mixture alone for several hours until the sand settled on the bottom of the container.  Is this mixture a solution, colloid, or suspension?

It is a suspension because the particles settle out over time.

500

How can mixtures be separated? Give an example. 

Mixtures are separated by playing upon different physical properties.  Examples include filtration and distillation.

Random

100

What is a substance that is made up of entirely one atom?

An element

200

List 3 physical changes.

Melting, mixing, separating, crushing, tearing, solid to liquid, liquid to gas, evaporating, dissolving, , grinding, and sanding.

300

How do gas particles move in solids, liquids, and gases? 

Solids- particles vibrate in place

Liquids- particles are free to move past each other

Gas- particles move freely/fast

400

Jack has a rock. The rock has a mass of 6g and a volume of 3cm³. What is the density of the rock?

D = m/v so the density of the rock equals 6/3. Density = 2 g/cm³.

500

Name two ways that compounds differ from mixtures? 

1. Mixtures can be physically separated

2. In mixures the substances keep their properties