activate 2 chemistry

acid rain:

Rain that has a non-metal dissolved in it.

chemical property:

How a substance behaves in its chemical reactions.

Density:

The mass of a material in a certain volume.

Displace:

A more reactive metal displaces - or pushes out - a less reactive metal from its compound.

displacement reaction:

In a displacement reaction, a more reactive metal displaces - or pushes out - a less reactive metal from its compound.

Group:

A vertical column of the Periodic Table. The elements in a group have similar properties.

Group 0:

Group 0 is on the right of the Periodic Table. Group 0 elements include helium, neon, argon, and krypton.

Group 1:

The elements in the left column of the Periodic Table, including lithium, sodium, and potassium.

Group 7:

Group 7 is the second from the right of the Periodic Table. Group 7 elements include fluorine, chlorine, bromine, and iodine.

Halogen:

Another name for the Group 7 elements.

Metal:

Elements on the left of the stepped line of the Periodic Table. Most elements are metals. They are good conductors of energy and electricity.

Metalloid:

Elements near the stepped line of the Periodic Table are metalloids.

noble gases:

Another name for the Group 0 elements.

non-metal:

Elements on the right of the stepped line of the Periodic Table. They are poor conductors of energy and electricity.

Period:

A horizontal row of the Periodic Table. There are trends in the properties of the elements across a period.

physical property:

A property of a material that you can observe or measure.

Reactive:

A substance is reactive if it reacts vigorously with substances such as dilute acids and water.

Unreactive:

Elements that take part in few chemical reactions are unreactive.

Atmosphere:

The mixture of gases surrounding the Earth.

biological weathering:

The breaking up or wearing down of rocks by the action of living things.

carbon cycle:

The carbon cycle shows stores of carbon, and summarises how carbon and its compounds enter and leave these stores.

carbon store:

A place where carbon and its compounds may remain for a long time. Carbon stores include the atmosphere, oceans, sedimentary rocks, fossil fuels, the soil, and living organisms.

Cementation:

The 'gluing together' of sediments by different chemicals to make sedimentary rocks.

chemical weathering:

The breaking up or wearing down of rocks by the action of chemicals such as those in rainwater.

climate change:

A long-term change in weather patterns.

Combustion:

A burning reaction, in which a substance reacts quickly with oxygen, and gives out light and heats the surroundings.

Compaction:

The process of squashing sediments together to make new rocks by the weight of layers above.

Crust:

The rocky outer layer of the Earth.

Deforestation:

The cutting down or burning of trees in forests.

Deposition:

The settling of sediments that have moved away from their original rock.

Durable:

A property of a material meaning that it is difficult to damage.

Erosion:

The breaking of a rock into sediments, and their movement away from the original rock.

freeze-thaw:

Weathering of rocks that happens as a result of water repeatedly freezing and thawing.

global warming:

The gradual increase in the Earth's mean air temperature.

greenhouse effect:

The absorbing of energy by gases in the atmosphere, such as carbon dioxide.

greenhouse gas:

A gas that contributes to climate change, such as carbon dioxide.

Igneous:

Rock made when liquid rock (magma or lava) cools and freezes.

inner core:

The solid iron and nickel at the centre of the Earth.

Lava:

Liquid rock that is above the Earth's surface.

Magma:

Liquid rock that is below the Earth's surface.

Mantle:

The layer of Earth that is below the crust. It is solid but can flow very slowly.

Metamorphic:

Rock formed by the action of heating and/or pressure on the sedimentary or igneous rock.

outer core:

The liquid iron and nickel between the Earth's mantle and inner core.

Photosynthesis:

The process plants use to make their own food, glucose. In photosynthesis, carbon dioxide and water react together to make glucose and oxygen.

physical weathering:

The breaking up or wearing down of rocks by the effects of changing temperature.

Porous:

A porous material has small gaps that may contain substances in their liquid or gas states. Water can soak into a porous material.

Radiation:

The transfer of energy as a wave.

Recycling:

Collecting and processing materials that have been used, to make new objects.

Respiration:

The process that transfers energy from plants and animals. In respiration, glucose reacts with oxygen to make carbon dioxide and water.

rock cycle:

The rock cycle explains how rocks change and are recycled into new rocks over millions of years.

Sediment:

Pieces of rock that have broken away from their original rock.

Sedimentary:

Rock made from sediments.

Transport:

Movement of sediments far from their original rock.

Troposphere:

The part of the atmosphere nearest the Earth.

Uplift:

Uplift happens when huge forces from inside the Earth push rocks upwards.

Weathering:

Weathering breaks up all types of rock into smaller pieces, called sediments.

carbon fibre:

A material made of thin tubes of carbon.

Ceramic:

A compound such as a metal silicate or oxide that is hard, strong, and has a high melting point.

Composite:

A mixture of materials with properties that are a combination of those of the materials in it.

Displace:

A more reactive metal displaces - or pushes out - a less reactive metal from its compound.

displacement reaction:

In a displacement reaction, a more reactive metal displaces - or pushes out - a less reactive metal from its compound.

Metal:

Elements on the left of the stepped line of the Periodic Table. Most elements are metals. They are good conductors of energy and electricity.

natural polymer:

Polymers made by plants and animals, including wool, cotton, and rubber.

Ore:

A rock that you can extract a metal from.

Polymer:

A substance made up of very long molecules.

Reactive:

A substance is reactive if it reacts vigorously with substances such as dilute acids and water.

reactivity series:

A list of metals in order of how vigorously they react.

state symbol:

A state symbol gives the state of a substance in a chemical equation. (s) means solid, (l) means liquid, (g) means gas, and (aq) means dissolved in water.

synthetic polymer:

A substance made up of very long molecules that does not occur naturally.

thermite reaction:

Reaction of aluminium with iron oxide to make aluminium oxide and iron.

Chromatogram:

An image obtained from chromatography.

Chromatography:

A technique to separate mixtures of liquids that are soluble in the same solvent.

Dissolve:

The mixing of a substance (the solute) with a liquid (the solvent) to make a solution.

Distillation:

A technique that uses evaporation and condensation to obtain a solvent from a solution.

Filtering:

A way of separating pieces of solid that are mixed with a liquid or solution by pouring through filter paper.

Filtrate:

The liquid or solution that collects in the container after the mixture has passed through the filter paper.

Filtration:

A way of separating pieces of solid that are mixed with a liquid or solution by pouring through filter paper.

Impure:

A substance is impure if it has different substances mixed with it.

Insoluble:

A substance that cannot dissolve in a certain solvent is insoluble in that solvent.

Mixture:

A mixture is made up of substances that are not chemically joined together.

Pure:

A substance is pure if it has no other substances mixed with it.

Residue:

The solid that collects in the filter paper.

saturated solution:

A solution in which no more solute can dissolve.

Solubility:

The solubility of a substance is the mass that dissolves in 100 g of water.

Solute:

The solid or gas that dissolves in a liquid.

Solution:

A mixture of a liquid with a solid or a gas. All parts of the mixture are the same.

Solvent:

The liquid in which a solid or gas dissolves.