Test Preparation grade7

The chemical equation shown below represents a reaction that produces fuel for certain cars.

CO + H₂O -> CO₂ + H₂

Which substance in this equation is classified as an element?

• CO

• H2O

• CO2

• H2

Hello, you can find me in sand, clay, glass, and volcanic eruption. I am used widely in semiconductor industries. Can you guess what element am I?

• K

• Ne

• S

• Si

Which one is the example of deposition / crystallization?

• Making dry ice (solid carbon dioxide)

• Naphthalene in cupboard change from solid to gas directly

• Morning dew above plants

• Change from water to water vapour

Which one element that DOESN’T HAVE exact atomic and mass number?

• H, atomic number 1, mass number 1

• O, atomic number 15, mass number 32

• Al, atomic number 13, mass number 27

• Ca, atomic number 20, mass number 40

What are the steps to make iron sulfide compound?

• Mix iron powder and sulfur powder, it’s enough

• Mix iron powder and sulfur powder, heat them

• Mix iron powder and sulfur powder, put it on refrigerator

• Mix iron powder and sulfur powder, separate them with magnet

This element has an atomic number of 15 and mass number of 31. We use it in matchbox and fertilisers. It’s also available on our bones and teeth. Can you tell what element is it?

• P

• N

• S

• Na

Complete this table below!

Sulfur dioxide

…. (Formula)

…… (What the compound contains)

Magnesium Oxide

……… (Formula)

…. (What the compound contains)

Calcium Chloride

….(Formula)

One calcium atom and two chlorine atoms

Lithium sulfate

…(Formula)

Two lithium atoms, one sulfur atom, and four oxygen atoms

Sodium Hydroxide

…(Formula)

One sodium atom, one oxygen atom, and one hydrogen atom.