Chemistry Y8 EOY exam Flashcards
(42 cards)
What are elements made up of?
Atoms that all have the same number of protons.
What are compounds made up of?
Atoms that have different numbers of protons that are bonded together.
Define a molecule.
A small number of atoms bonded together - they can be elements or compounds.
What happens to the metals as you go down group 1?
The metals get more reactive and have lower melting points.
What trend occurs in group 7 as you go down?
The elements get less reactive, have higher melting points, and get darker.
What happens to the elements (noble gases) in group 0 as you go down?
The boiling points go up, but reactivity doesn’t change.
What does accuracy refer to in measurements?
How close a measurement is to the true value.
What does reliability refer to in experiments?
The consistency of results when an experiment is repeated.
What is the independent variable?
The variable that is intentionally changed or manipulated in an experiment.
What is the dependent variable?
The variable that is measured or observed in response to changes in the independent variable.
What are control variables?
Variables that are kept constant to ensure that the effect on the dependent variable is solely due to changes in the independent variable.
How can you ensure accurate results?
Use calibrated instruments, control errors, and take multiple measurements to minimise mistakes.
How can you ensure reliable results?
Repeat the experiment multiple times to check for consistency and reduce random errors.
What are composite materials made from?
Two or more different types of material.
Why are materials chosen for composite materials?
They have different properties that combine to make a more useful material.
Why is reinforced concrete strong when stretched?
Because of the steel.
Why is reinforced concrete strong when squashed?
Because of the concrete.
What are breathable fabrics designed to do?
Stop raindrops getting in while letting water vapour from sweat pass to the outside.
What are polymers?
Long molecules that are built by combining many monomers.
What is the most common type of polymer?
Plastic.
List some properties of plastics.
- Chemically unreactive
- Solid at room temp
- Can be moulded into shape
- Electrical insulator
- Strong and hard-wearing
What are ceramics made from?
Soft substances, which when heated become hard and brittle.
List common properties of ceramics.
- Hardness
- Strong under compression
- Brittle
- Heat resistant
What is RAM (relative atomic mass)?
The mass in the nucleus of an atom.
