Science- Chemical Changes

Which of the following substances will react with hydrochloric acid to produce hydrogen gas?

• calcium carbonate

• sodium hydroxide

• zinc oxide

• calcium

Which reaction does NOT produce carbon dioxide gas?

• Burning of fuel

• Thermal decomposition of zinc carbonate

• Reaction of calcium hydroxide and hydrochloric acid

• Respiration

Which of the following is NOT a product formed when sulfuric acid reacts magnesium carbonate?

• magnesium sulfate

• hydrogen gas

• water

• carbon dioxide

The salt calcium nitrate is formed when two colourless solutions are mixed. What are the two possible solutions?

• calcium + sodium nitrate

• nitric acid + calcium hydroxide

• potassium nitrate + hydrochloric acid

• nitric acid + calcium sulfate

A sweet contains citric acid and some chemicals. When the sweet is put into your mouth, it mixes with the water and fizzes, producing a gas. Which of the following can be found in the sweet?

• sodium carbonate

• ammonium sulfate

• sodium oxide

• sodium hydroxide

A conical flask contains sodium hydroxide and methyl orange indicator. Hydrochloric acid is added to the conical flask drop by drop until there is excess acid. What is the expected colour change?

• red to orange

• yellow to orange

• red to yellow

• yellow to red

Which of the following is NOT an example of neutralisation in our daily lives?

• Using a plastic container instead of a metal container to hold vinegar (ethanoic acid)

• Washing our hair with conditioner(acidic) to reduce the effects of shampoo(alkaline) on our hair

• Using vinegar (acidic) to clean a sting by a wasp (alkaline)

• Brushing our teeth with toothpaste(alkaline)

What is the test for hydrogen gas?

• It extinguishes a glowing splint with a pop sound.

• It extinguishes a lighted splint with a pop sound.

• It gives a white precipitate in limewater.

• It produces effervescence in acid.