Sec 2 Science Chemical Changes topical questions

State what makes a change a chemical change, and give one example.

Complete the word equation: magnesium + oxygen →

State the colour of litmus in an acid and in an alkali.

Name the two products when an acid reacts with an alkali.

Name one natural indicator.

Explain why the total mass stays the same when magnesium burns in a closed flask.

Iron nails rust in damp air. Explain why this is oxidation, and state two substances needed besides iron.

Describe thermal decomposition using calcium carbonate as the example. A word equation is enough.

Acid is added to a carbonate. A gas is given off that turns limewater milky. Name the gas and the type of observation that shows a chemical change.

Explain the difference between litmus and Universal Indicator.

A student heats a beaker and the mass of the contents falls. The student says atoms were destroyed. Evaluate the claim.

Compare combustion of a fuel with respiration in a cell. State one similarity and one difference.

Write a word equation for the reaction of hydrochloric acid with sodium hydroxide, and state the colour of Universal Indicator before and after the solution becomes neutral.

Explain why painting an iron gate slows rusting, using the substances rusting needs.

Magnesium reacts with hydrochloric acid and a gas pops with a lighted splint. Name the gas and write the word equation.