Chemistry Exam Revision

Chemistry

What is Filtration used for?

To separate solids from liquids or gases using a filter.

What is Evaporation?

A process that separates a soluble solid from a liquid by heating until the liquid turns into vapor.

What does Distillation do?

Separates substances based on differences in boiling points.

What is Chromatography?

A method used to separate mixtures based on the movement of different components through a medium.

How does Centrifugation work?

It utilizes centrifugal force to separate substances of different densities.

What is Decantation?

Pouring off a liquid to leave behind solid sediments or another liquid.

Define a Solid in terms of particle arrangement.

Has a definite shape and volume; particles are closely packed and vibrate in place.

How would you describe a Liquid?

Has a definite volume but takes the shape of its container; particles move past one another.

What is a Gas?

Has no definite shape or volume; particles are far apart and move freely.

What is Plasma?

A state of matter consisting of ionized gas with free-moving ions and electrons.

How is density defined?

Density is mass per unit volume.

What is the formula for calculating Density?

Density = Mass / Volume.

What characterizes a Homogeneous mixture?

It has the same uniform appearance and composition throughout.

Describe a Heterogeneous mixture.

It consists of visibly different substances or different states of matter.

What is a Pure substance?

A substance made up of only one type of matter.

Define an Impure substance.

A substance made up of different particle types; another name for a mixture.

What are Solutions?

Mixtures in which the particles are so small that they're invisible and do not scatter light.

How does Concentration relate to solutions?

Concentration refers to the amount of solute dissolved in a solvent.

What is a Dilute solution?

A solution with little dissolved solute.

What defines a Suspension?

A mixture where particles of one component are suspended in another; they can be seen.

What is a Colloid?

A mixture where particles are small enough to stay suspended even when left to stand.

What components make up an atom?

Protons, neutrons, electrons and electron shells.

What does the atomic number represent?

The number of protons in an atom.

How do you determine the atomic mass?

It is the sum of the number of protons and neutrons.

How can you read the periodic table?

By drawing the basic structure of the atom including electron shells for any of the first 20 elements.

What role does density play in centrifugation?

It allows for the separation of substances based on their different densities.

What is a characteristic of solutions?

They are transparent and can still be colored.

Why are pure substances rare in nature?

Because even seemingly pure substances often contain mixtures of different chemical compounds.

What happens when motion stops in a suspension?

The components of the mixture separate from each other.

In what states of matter can suspensions be found?

Solid mixed into a liquid, gas mixed into a liquid, and various combinations.

What happens to particles in a colloid?

They do not separate and stay suspended even when left to stand.

What is required to keep particle suspended in a suspension?

A shaking, stirring, or flowing motion.