Y1 Chemistry STAR (29 Jul) Part I

What is an element?

• A substance consisting of two or more substances mixed together.

• A substance that cannot be broken down into anything simpler.

• A substance consisting of two or more elements chemically combined.

• A substance that can be easily separated by physical means.

What is a characteristic property of sulfur?

• It is a dark grey crystal.

• It sinks in water.

• It is attracted to a magnet.

• It is a bright yellow powder.

How does a mixture of iron and sulfur behave compared to the individual elements when tested with water?

• The iron and sulfur remain mixed and sink together.

• The iron sinks and the sulfur floats, allowing them to be separated.

• Both the iron and sulfur float.

• Both the iron and sulfur dissolve in water.

What happens when hydrochloric acid is added to Iron(II) Sulfide?

• Hydrogen gas is produced, which gives a pop test.

• No visible reaction occurs.

• Hydrogen sulfide gas is produced, which is toxic.

• The compound separates back into iron and sulfur.

What is a key difference between a mixture and a compound, as demonstrated by the experiments?

• Mixtures can be separated by physical means, while compounds cannot.

• Compounds retain the properties of their original elements, while mixtures do not.

• Mixtures are formed by chemical bonding, while compounds are not.

• Compounds always have a bright yellow appearance, while mixtures are dark grey.