science respiration chemical energy magnetism

Magnet

a magnet has 2 poles, north and south.

south poles

south poles attract north poles and repel south poles.

north poles

north poles attract south poles and repel north poles.

what are the three magnetic materials?

iron, nickel, cobalt

magnetic materials

magnetic materials will experience a magnetic force when placed near a magnet.

what type of force is that magnetic force?

the force is a type of non-contact force because the materials do not have to touch for the force to be apparent.

how are electromagnets made?

electromagnets are made by wrapping a coil of wire around a magnetic core.

when do electromagnets work?

electromagnets only work when electricity is flowing through the coil, meaning they can be turned off and on.

Are electromagnets stronger or weaker than permanent magnets?

stronger

What type of magnetic field shape will the electromagnet produce?

The electromagnet will produce the same magnetic field shape as a bar magnet

how can you increase the strength of an electromagnet?

you can increase the strength of an electromagnet by:

-increasing the number of turns on the coil around the core of the electromagnet

-increasing the current which is flowing through the coil of wire

-using a more magnetic material for the core, eg. iron rather than aluminium

exothermic reactions

exothermic reactions involve a transfer of energy from the reactants to the surroundings.

will the temperature change in an exothermic reaction?

as energy is transferred to the surroundings this will show an increase in temperature.

Examples of exothermic reactions

examples of exothermic reactions include combustion, freezing and condensing.

Endothermic reactions

Endothermic reactions involve a transfer of energy from the surroundings to the reactant’

How will the temperature change in an endothermic reaction?

As energy is taken into the reactants a decrease in temperature will be shown.

Examples of endothermic reactions

Examples of endothermic reactions include thermal decomposition, melting and boiling.

Energy level diagrams

Energy level diagrams show the values of energy between the reactants and the products in a reaction.

How to tell from an energy level diagram if the reaction is exothermic?

If the energy is greater in the reactants than the products then the reaction is exothermic as energy has been given out to the surroundings.

How to tell from an energy level diagram if the reaction is endothermic?

If the energy is lower in the reactants than the products then the reaction is endothermic as energy has been taken into from the surroundings.

Why is melting endothermic?

In ice, forces of attraction hold water molecules in a pattern. When energy is transferred to the ice, these forces are disrupted. The water molecules move out of their arrangement, and the ice melts.

Respiration

Living organisms carry out respiration to release energy.

is respiration the same as breathing?

respiration is NOT the same as breathing.respiration is a chemical reaction that takes place inside cells.

What life processes are the energy released by respiration used for?

-Growth and repair of cells

-Movement

-Control of body temperature in mammals

Aerobic respiration

Aerobic respiration is respiration involving the use of oxygen.

What is the word equation for aerobic respiration?

Glucose + oxygen ———→ carbon dioxide + water (+ energy)

Where does respiration take place?

Respiration takes place in mitochondria in animal and plant cells.

Anaerobic respiration

Anaerobic respiration occurs in the absence of oxygen and usually occurs during strenuous exercise.

What is the word equation for anaerobic respiration?

The word equation for anaerobic respiration in animals is glucose ————→ lactic acid (+energy)

Does anaerobic respiration release more or less energy than aerobic respiration?

Anaerobic respiration releases less energy than aerobic respiration.

What can build up in the muscles during exercise?

Lactic acid can build up in the muscles during exercise, which can lead to cramp.

Fermentation

Fermentation is a type of anaerobic respiration carried out in plant cells and some microorganisms like yeast.

What is the word equation for fermentation?

The word equation for fermentation is glucose ——————→ ethanol + carbon dioxide (+energy)

Examples of products produced by fermentation

Bread and alcoholic drinks such as beer.

What is a variable?

In science, anything that can change during an investigation, such as the temperature, is called a variable.

What else can be a variable?

The thing that is affected as a result of the change is also a variable.