Chemistry

Question 1

Compound

Answer 1

A combination of two or more elements, bonded in some way.

Example: H2O (water)

Question 2

Binary

Answer 2

A compound composed of two elements only.

Example: carbon monoxide (CO)

Question 3

Atom

Answer 3

• The smallest particle of an element that retains the chemical properties of that element.

ALSO

• they are the smallest unit into which matter can be divided without the release of electrically charged particles.

Question 4

How many elements are there?

Answer 4

118

Question 5

Element

Answer 5

• A substance which cannot be split into simpler substances by a chemical reaction.
• they are the fundamental materials by which all matter is composed.

Example: H (hydrogen atom)

Question 6

Nuclear fission

Answer 6

• The division of a nucleus of an atom.

- caused by bombardment with a neutron (a subatomic particle).

Question 7

What is the affect of nuclear fission?

Answer 7

When a neutron splits an atom:

• it forms neutrons and nuclei of other elements.
• it releases huge amounts of energy.
• the release of neutrons also causes the fission of other atoms, which in turn produces more neutrons.
• this leads to a chain reaction.

Question 8

When is nuclear fission used?

Answer 8

• controlled nuclear fission is used in nuclear power stations.
• uncontrolled fission (atom bombs) is very explosive.

Question 9

Nuclear fusion

Answer 9

The combination of:

• two nuclei to form a larger one.
• it will only take place at extremely high temperatures.
• releases huge amounts of energy.
• nuclear fusion takes place in the hydrogen bomb.