Chemistry Y8

Conservation of mass means

• all the atoms present before a chemical reaction are not present after

• atoms present before chemical reactions are present after

• new substances and new elements are formed in a chemical reaction

A pure substance that is a compound is made out of

• particles of more than one type of atom

• particles of the same type of atom

• a mixture of two or more substances that can be physically separated

Signs of a chemical change include;

• change of colour, change of temperature, precipitate (solid) formed, gas released.

• change of colour, reversing back to original form, precipitate (solid) formed, gas released.

When an acid reacts with a metal following is the product

• salt + hydrogen

• salt + carbon dioxide + water

What is the chemical symbol for carbon?

• C

• Ca

• Cn

• Crn

Acid + Metal --> ?

• Salt + Water
• Salt + Hydrogen
• Salt
• Hydrogen

Iron + Hydrochloric acid --> ?

• iron sulfate + water
• iron + hydrogen
• iron chloride + hydrogen
• iron chloride + water

Magnesium + sulphuric acid --> ?

• magnesium sulfate + water
• magnesium sulfate + hydrogen
• magnesium chloride + hydrogen
• magnesium chloride + water

Which gas gives out a 'squeaky pop' when a lit splint is placed in it?

• hydrogen
• oxygen
• carbon dioxide
• nitrogen

Which metal is the least reactive out of: copper, magnesium, zinc and iron?

• copper
• magnesium
• zinc
• iron