chemistry snhs y9

The hotter a solid gets…

the faster it’s particles vibrate

What happens when solids are heated?

They expand

Can solids flow like liquids?

No

How do solids move?

By vibrating about a fixed position

How are solids arranged?

In a regular way

What holds the particles together and keeps them in place?

Forces of attraction

Can solids usually be compressed or squashed?

No

How are solids structured?

Fixed

How are particles in liquids arranged?

In a random way, close together, touching many of their neighbours

Can liquids usually be compressed or squashed?

No

Can particles in liquids move around and move over each other, allowing liquids to flow and be poured?

Yes

Is there only one type of gas?

No

How are particles in gases arranged?

Widely spaced and randomly arranged

Can particles in gases be easily compressed or squashed?

Yes

The particles in a gas have enough energy to…

Overcome the forces of attraction between the particles, so are free to move in any direction

How do particles in a gas move?

Quickly in straight lines, colliding with each other and the walls of their container

What is evaporation?

The process of a liquid turning into a gas

Does boiling happen faster than evaporation?

Yes

At what temperatures does evaporation occur?

All temperatures

Does boiling happen at a fixed temperature?

Yes

What is distillation?

A separation technique used to separate a solvent from a mixture

What does distillation involve?

Boiling the mixture and then condensing the gas to produce a liquid

What is chromatography?

A separation technique used to separate mixtures of soluble substances

What can chromatograms be used for?

To match known pigments with those in a mixture

In chemistry, what is a pure substance?

A single substance made of only one type of particle

What changes the temperature at which a substance melts and boils?

Impurities

What is an impurity?

A substance that consists of more than one element or compound

How is a solution made?

When a solute dissolves into a solvent

If a substance can dissolve into a solvent, what is it?

A soluble

Is a substance cannot dissolve, what is it?

Insoluble

What are ways to speed up dissolving?

Heating, stirring and using fine powders

What is diffusion?

The movement of a substance from an area of high concentration to an area of lower concentration

Where does diffusion occur?

In liquids and gases

When is filtration used?

To separate an insolvable solid from a pure liquid or a solution

What’s matter made out of?

Atoms

What is an element?

A substance made up of only one kind of atom

What is the relative electric charge of a proton?

+1

What is the relative electric charge of a neutron?

0 (neutral)

What is the relative elective charge of an electron?

-1

What is the relative mass of a proton?

1

What is the relative mass of a neutron?

1

What is the relative mass of an electron?

1/1840

What are particles diagrams used for?

To help explain elements, compounds and mixtures

What do some individual atoms do?

Bond together to form molecules of atoms of the same element

What element comes first when naming compunds?

The furthest left in the periodic table

If the compound contains three elements one of which is oxygen then the compound name will end in…

-ate or -ite (eg. Calcium carbonate contains calcium, carbon and oxygen)

What do compounds contain?

Atoms of different elements, chemically joined together

What do word equations not show?

Any chemical symbols or formulae

How do you write a word equation?

Reactants —>products. A + sign separates two or more reactants or products

What is the chart all elements are arranged in?

The periodic table

What is the arrangement of the elements based on?

Their structure and properties

Who produced one of the first practical periodic tables?

Dmitri Mendeleev

What are the horizontal rows on a periodic table called?

Periods

What are the vertical columns called on a periodic table?

Groups

Where are the metals in the periodic table?

Left

What are the physical properties of alkali metals?

They are soft and have relatively low melting points

What are the elements in group 7 called?

Halogens

What happens in a displacement reaction?

A more reactive metal will displace a less reactive metal from its compound

What are the 3 different types of rock found on earth?

Igneous, metamorphic and sedimentary

What gases is the atmosphere mostly made out of?

Nitrogen (approx. 80%) and oxygen (approx. 20%)

From the first to third electron shell, how many electrons can they each hold?

2, 8, 8

What are ionic bonds formed between?

A metal and non-metal

How is a covalent bond formed?

When two atoms have a shared pair of electrons