science

which statement about evaporation is correct?

• evaporation causes the temperature of the remaining liquid to decrease

• evaporation is a fast process of turning liquid into gas

• evaporation occurs only above the boiling point of the liquid

• evaporation occurs from all parts of a liquid

Smoke particles, illuminated by a bright light, are seen through a microscope. they move about randomly. what causes this motion?

• attraction between the smoke particles and the molecules of the air

• collisions between the smoke particles and the molecules of the air

• evaporation of the faster moving smoke particles

• warming of the smoke particles by the lamp

look at the diagram . the diagram represents

• element in solid form

• compounds in solid form

• element in gaseous form

• compounds in solid form

all matter is made up of very small particles that are constantly in motion. this theory is called

• Kinetic particle theory

• motion sea particle theory

• brown motion theory

• potential particle theory

take a look at the heating graph of water below

which line segment represents the melting point of water?

• A

• B

• D

• C

A substance has a melting and boiling point of 5 degrees celcius and 67 degrees celcius respectively. the state of this substance at 54 degrees celcius is

• solid

• liquid

• gas

• plasma

which line segment below indicates boiling

• AB

• CD

• BC

• DE

Which segment below represent gas?

• AB

• CD

• EF

• DE

Average distance Average speed

of the particles between the particles

A greater in the liquid greater in the liquid

B greater in the liquid smaller in the liquid

C smaller in the liquid greater in the liquid

D smaller in the liquid smaller in the liquid

which row correctly compared liquid with gas?

• option C

• Option B

• Option D

• Option A

What causes the random zig zag movement ( brownian movement ) of smoke particles suspended in the air

• air molecules colliding with smoke particles

• convection currents as the hot smoke rises

• smoke particles colliding with each other

• smoke particles reacting with oxygen molecules in the air