Chemistry topic 1: Principles of chemistry

Question 1

Whats a solid?

Answer 1

A group of particles tightly packed together in the same position and only vibrating

Question 2

Whats a liquid?

Answer 2

A group of particles close together but are free to move around each other. (More kinetic energy then solids)

Question 3

Whats a gas?

Answer 3

A gas is particles moving in random directions at a fast rate.
They have the most kinetic energy out of all the states of matter

Question 4

What is diffusion?

Answer 4

Particles moving from an area of high concentration to an area of low concentration

Question 5

What is dilution?

Answer 5

Dilution is when you add a solvent into a solution

Question 6

What is a solvent?

Answer 6

The liquid in which a solute dissolves

Question 7

What is a solute?

Answer 7

The substance which dissolves in a liquid to form a solution

Question 8

What is a solution?

Answer 8

The mixture formed when a solute is dissolved in a solvent

Question 9

What is a saturated solution?

Answer 9

A solution with the maximum concentration of solute dissolved in the solvent at a particular temp.

Question 10

What is meant by soluble?

Answer 10

A substance that can dissolve

Question 11

What is meant by insoluble?

Answer 11

A substance that is unable to dissolve

Question 12

What is an element?

Answer 12

A substance made of only one type of atom.

Question 13

What is a compound?

Answer 13

A pure substance made up of two or more different elements chemically combined

Question 14

What is a mixture?

Answer 14

A combination of two or more substances (elements and/or compounds) that are not chemically bonded

Question 15

What is the boiling point?

Answer 15

The temperature in which a substance changes state from a liquid to a gas

Question 16

What is the freezing point?

Answer 16

The temperature in which a substance changes state from a liquid to solid

Question 17

What is a pure substance?

Answer 17

A substance that contains a single element or compound and does not contain any other substance

Question 18

True or false? Pure substances melt and boil at specific and sharp temperatures

Answer 18

True

Question 19

True or false? Impure substances have a single melting and boiling point as they consist of different substances

Answer 19

False. Impure substances has a range of different melting and boiling points as they consist of different substances

Question 20

What is fractional distillation?

Answer 20

Fractional distillation is the process of separating 2 or more liquids that cannot be mixed.

Question 21

How does fractional distillation done?

Answer 21

Fractional distillation is done by boiling the solution and the solution with the lowest boiling points gets boiled and the vapour goes through a condenser in which changes the gas to a liquid and so this liquid gets extracted into another beaker successfully separating the liquids apart.

Question 22

What is simple distillation?

Answer 22

Simple distillation is the process of separating a soluble solid and a liquid from a solution

Question 23

How does simple distillation work?

Answer 23

The solution is heated and the pure liquid of the solution gets turned into vapour which then gets condensed by a condenser changing the vapour into a liquid. This separates the liquid from the soluble solid. And so the solute gets left behind.

Question 24

What is filtration?

Answer 24

Filtration is the process used to separate an insoluble solid from a liquid

Question 25

How does filtration work?

Answer 25

A piece of filter paper is placed above the beaker. The solution is poured above the beaker where the filter paper is. The filter paper only allows small liquid particles to pass through. Leaving behind the solute In the filter paper.

Question 26

What is crystallisation?

Answer 26

Crystallisation is used to separate a dissolved solid from a solution

Question 27

How does crystallisation work?

Answer 27

The solution is heated allowing the solvent to evaporate. This leaves a saturated solution behind. The saturated solution cools slowly. Crystals will start to form as solids will come out of the solution due to decreasing solubility. The crystals are collected by filtering the solution, they are washed with cold distilled water to remove impurities and are then allowed to dry.