Circuits & Acids Test

Chemical reaction

A change in which atoms are rearranged to create new substances. The atoms are joined together in a different way before the reaction and after the reaction.

Physical change

Involves a change in particle's arrangement, movement, and energy only – the particles themselves don’t change.

Toxic

A substance that is poisonous and therefore extremely hazardous to human health.

Flammable

A substance that can catch fire easily.

Health hazard (harmful)

A substance that contains anything that could be harmful for human health (but not as deadly as toxic).

Caution (irritant)

A substance that could be an irritant, something that is mildly harmful or a low-hazard substance.

Corrosive

A substance that may dissolve or burn materials, including skin.

Explosive

A substance that may explode.

Concentration

The amount of a solid dissolved per unit volume of liquid, usually measured in g/cm³.

Concentrated

A solution that contains a lot of particles in a given volume.

Dilute

A solution that contains few particles in a given volume.

Acid

A substance that contains H⁺ (acid) particles when dissolved in water.

Alkali

A substance that contains OH⁻ (alkali) particles when dissolved in water.

Base

Any substance that reacts with an acid (can be insoluble).

Neutralisation

A reaction where an acid reacts with an alkali, usually the symbol for the reaction is H⁺ + OH⁻ H₂O.

Universal indicator

An indicator that has a wide range of colours that depend on the pH of the solution.

Litmus

An indicator that changes to red in acidic solutions and blue in alkali solutions.

pH scale

The scale to show how acidic or alkaline a solution is. The lower the pH, the more concentrated the acid particles in solution are.

Strong acid

Something that releases a lot of H⁺ (acid) particles when dissolved in solution.

Weak acid

Something that releases few H⁺ (acid) particles when dissolved in solution.

Salt

A substance made from a metal and non-metal that is always produced in a neutralisation reaction.

Current

The number of charges passing a point every second, measured in Amps.

Potential Difference

The amount of energy transferred per charge every second, measured in Volts.

Resistance

How difficult it is for charges to pass through a component in a circuit.

Bulb/Lamp

A device in a circuit that transfers electrical energy into light and heat.

Cell

A device that provides a push for the charges to flow around a circuit.

Series

When two components are connected in the same branch of a circuit to each other.

Parallel

When two components are connected in a different branch of a circuit to each other.

Ammeter

A device for measuring the current at any point in a circuit, connected in series in a circuit.

Voltmeter

A device for measuring the potential difference of a component, connected in parallel to a component.

Model

A way of representing a difficult concept in Science by linking it to a 'real-life' situation.

Conductor

A device in a circuit that has a low resistance and therefore allows current to pass through.

Insulator

A device in a circuit that has a high resistance and therefore does not allow a current to pass through.

Electron

A charged particle that moves around a circuit; how quickly they move is known as the current.

Battery

A series of cells connected together.

Switch

A device in a circuit used to break the circuit to stop current from flowing, having open and closed positions.

Resistor

Something that stops a large current from flowing and resists the motion of electrons around the circuit.