Grade 6 Chemical Reactions

Which of the following is NOT a physical property of a substance?

• How it reacts with another substance

• Its shape

• Its colour

• Its melting point

When a piece of wood is set on fire,

• A chemical change takes place.

• A physical change takes place

• A physical and chemical change takes place

• None of these happen

When water freezes,

• A physical change takes place.

• A chemical change takes place.

• A physical and chemical change takes place.

• None of these.

When magnesium is burnt in air, a new substance is formed. The new substance is the...

• Reactant of the reaction

• Product of the reaction

• By product of the reaction

• Waste of the reaction

What does magnesium react with, when it is burnt in air?

• Nitrogen

• Oxygen

• Helium

• Carbon dioxide

If the ash produced when magnesium is burnt in air is mixed into a beaker of water and a few drops of phenolthalien are added, the water will turn a

• Pink colour

• Blue colour

• Yellow colour

• Green colour

The colour the solution turns in the presence of phenolthalien shows you that the solution is

• Acidic

• Alkaline

• Neutral

• Sour

When a piece of magnesium ribbon is placed into a test tube containing some hydrochloric acid, a reaction takes place. We know this because...

• The magnesium starts to fizz and produce carbon dioxide gas.

• The temperature of the test tube increases

• The temperature of the test tube decreases

• The temperature of the test tube increases and hydrogen gas is produced.

In the reaction between magnesium and hydrochloric acid, the magnesium and the hydorchloric acid are the .........

• Reactants

• Products

• Solute and solvent

• None of these

In the reaction between magnesium and hydrochloric acid, the magnesium will ....

• Increase the pH of the hydrochloric acid.

• Decrease the pH of the hydrochloric acid

• Will increase then decrease the pH of the hydrochloric acid

• Have no effect on the pH of the hydrochloric acid.