Heating sugar

The idea

On heating, sugar decomposes into carbon and water, so it cannot be an element; it is a compound of the elements carbon, hydrogen and oxygen.

Heat some sugar

Dry sugar is heated in a tube.

What do you expect to see?

• It turns brown, then black, with water droplets
• Nothing happens
• It becomes a metal

Heat the sugar

Press Next step to heat.

A compound of three elements

Sugar breaks into carbon and water. Water is made of hydrogen and oxygen. So sugar cannot be an element.

Heating decomposes sugar into carbon and water. So sugar is a compound of carbon, hydrogen and oxygen.

Notes

Sugar breaks into carbon and water, so it is a compound of carbon, hydrogen and oxygen.

Check yourself

When sugar is heated, it finally leaves behind …

The water droplets seen while heating sugar came from …

Sugar decomposes into carbon and water, so it cannot be …

Sugar is a compound of the elements …

• iron. Carbon (charcoal) is left behind.
• salt. Carbon (charcoal) is left behind.
• carbon — correct. Yes!
• the sugar — correct. Yes!
• the air. The tube was being heated, so the water came from the dry sugar.
• the flame only. The water came from the sugar.
• a compound. It is a compound.
• an element — correct. Yes!
• a substance. It is a substance. It is not an element.
• iron and sulfur. That would be iron sulfide.
• sodium and chlorine. That is sodium chloride.
• carbon, hydrogen and oxygen — correct. Yes!