end of year 8 test science

Question 1

properties of metals

Answer 1

good conductors of heat and electricity,
shiny,
solids with a high melting point,
flexible and malleable

Question 2

properties of non-metals

Answer 2

poor conductors of electricity and heat
dull
most are low melting point solids or gases
brittle (break easily instead of bending)

Question 3

state some uses of metals

Answer 3

e.g. copper is used in electrical wires as it is flexible and good conductor of electricity

Question 4

what is a catalyst?

Answer 4

A catalyst is a substance that speeds up a reaction without being used up

Question 5

Potassium + oxygen = ?

Answer 5

potassium + oxygen= potassium oxide

Question 6

what is rusting

Answer 6

rusting is the corrosion of iron

Question 7

what is the formula for rust

Answer 7

iron + water + oxygen = iron hydroxide

Question 8

word equation for how water reacts with metals

Answer 8

metal + water = metal hydroxide + hydrogen

Question 9

what is the test for hydrogen gas?

Answer 9

a burning splint should go of with a squeaky pop sound if hydrogen is available

Question 10

what is the test for oxygen ?

Answer 10

get a glowing splint and place it in oxygen and it should relight

Question 11

what is the test for carbon dioxide?

Answer 11

bubble carbon dioxide into limewater and if carbon dioxide is there is should turn MILKY

Question 12

what is the reaction of an acid and a metal ?

Answer 12

metal + acid = salt + hydrogen

Question 13

why are alloys better than metals/elements?

Answer 13

because they are stronger, melt over a range of melting points, prevent corrosion and etc.

Question 14

why are alloys stronger than elements?

Answer 14

because alloys have different shaped atoms which disrupt the regular structure making it harder for the layers to slip over each other.

Question 15

what is Dalton’s atomic theory

Answer 15

All matter is made up of tiny particles called atoms.
Atoms are indestructible, and cannot be created, or destroyed.
The atoms in an element are all identical.
During chemical reactions, atoms rearrange to make new substances.

Question 16

what are some chemical changes?

Answer 16

some example of chemical changes are colour change, bubbles( formation of a gas), surroundings increasing or decreasing temperature and change in smell.

Question 17

what is the law of reflection?

Answer 17

angle of incidence is equal to the angle of reflection if the surface is flat.

Question 18

what is diffuse reflection?

Answer 18

the angle of incident is not the same as angle of reflection.

Question 19

what are the Types of lenses?

Answer 19

Concave lens: The centre of the concave lens is thinner than the edges.
Convex lens: The centre of the convex lens is thicker than the edges.

Question 20

What is refraction?

Answer 20

refraction is when light bends when going through a translucent or transparent material.

Question 21

what is focal length?

Answer 21

focal length is the distance between the centre of the lens and the focal point.

Question 22

name two specialised cells in the eye?

Answer 22

cone cells- allow you to see colour

rod cells- react to light

Question 23

name three primary colours?

Answer 23

blue,red,yellow

Question 24

what are the parts of a sound wave?

Answer 24

https://www.google.com/search?q=parts+of+a+sound+wave&rlz=1C1CHBF_en-GBGB972GB972&sxsrf=ALiCzsYcVdrEwqlbH6g-KVtDY-gcm2OmYw:1655653029121&source=lnms&tbm=isch&sa=X&ved=2ahUKEwj646-V7Ln4AhWxmFwKHVRzB0UQ_AUoAXoECAEQAw&biw=1440&bih=757&dpr=1#imgrc=2ydSSvvBbjQdmM

Question 25

where does gas exchange take place?

Answer 25

alveoli

Question 26

what is the difference of respiration and breathing?

Answer 26

respiration is the chemical reaction of oxygen and glucose but breathing is the movement of muscles to inhale and exhale and this is done by the help of the diaphragm.

Question 27

What is a longitudinal Wave (Sound)

Answer 27

The particles vibrate in the same direction as the sound wave

Question 28

What is a transverse wave (Sound)

Answer 28

A transverse wave is the vibration of particles to a 90 degree angle of the wave