Year 7 States Of Matter And Atoms

Question 1

Features of a solid

Answer 1

Atoms/molecules are held together by strong forces of attraction
Particles can’t move over each other but they can vibrate

Question 2

Features of a liquid

Answer 2

Atoms/molecules are held together by weaker forces of attraction (intermolecular forces)
Particles are slightly further apart and can move around each other

Question 3

Features of a gas

Answer 3

Atoms/molecules are held together by weaker forces of attraction (inter molecular forces)
Particles are very far apart, and they move in all directions

Question 4

What is the water cycle?

Answer 4

subliming
melting evaporating
SOLID LIQUID GAS
freezing/solidifying condensing
subliming

Question 5

What is diffusion?

Answer 5

The movement of particles from an area of high concentration to an area of low concentration

Question 6

What is an example of a diffusion experiment?

Answer 6

Start with two glass jars: one containing nitrogen dioxide (NO2) and the other contains air.
After about 2mins, both jars have turned lighter brown because the NO2 molecules diffused from the area of high NO2 concentration to the area of low NO2 concentration (the air) and vice versa.

Question 7

What is the technique that is used to separate an insoluble solid from a liquid?

Answer 7

Filtration—>pour the mixture into filter paper in a funnel. The liquid flows into the flask and is called filtrate and the solid left in the filter paper if called residue

Question 8

What is the technique used to separate a soluble solid from a liquid?

Answer 8

Evaporation—>heat the solution in an evaporating dish, and then the liquid evaporates and turns into water vapour and the solid is left behind

Question 9

What is the technique that is used to super ate an insoluble solid from a liquid?

Answer 9

Decanting—>the water is poured into a flask and the solid is left behind in the first beaker

Question 10

What is a mixture?

Answer 10

The different substances in a mixture are separate from one another and are not chemically joined when they are mixed together, so we can separate them out again

Question 11

What is the technique that is used to separate two liquids that mix together?

Answer 11

Distillation

Question 12

What is the technique that is used to separate two liquids that do not mix together?

Answer 12

Using a separating funnel—>liquids that don’t mix together are called immiscible as they have different densities, eg. Oil and water

Question 13

What is the technique that is used to separate mixtures that when mixed together are soluble?

Answer 13

Chromatography—>put a drop of each colour onto the chromatography paper then dip it in water and leave it. The colours rise up the paper depending on how soluble they are. (Insoluble–>stays at bottom, soluble–>rises to top)

Question 14

What is an element?

Answer 14

A chemical substance that can’t be broken down into anything simpler. It consists of only one type of atom.

Question 15

What is a molecule?

Answer 15

Two or more atoms joined together

Question 16

What is a compound?

Answer 16

Molecules made of two or more types of atoms

Question 17

What is a mixture?

Answer 17

Two or more types of elements or compounds mixed together, not joined by bonds

Question 18

What is the difference between a mixture and a compound?

Answer 18

A mixture is when you have two or more types of elements or compounds mixed together but not chemically bonded, so they’re unattached. A compound is when there are two or more types of atoms, but they are bonded together, therefore they are attached.

Question 19

What is an element?

Answer 19

Atoms or molecules made of one type of atom