Formulae

What is a key characteristic of compounds in terms of their atomic composition?

• They consist of atoms in a fixed ratio.

• They consist of atoms in a random ratio.

• They consist of atoms in a variable ratio.

• They consist of atoms in a changing ratio.

What does the chemical formula NaCl represent?

• A compound with two sodium atoms and one chlorine atom.

• A compound with one sodium atom and one chlorine atom.

• A compound with two sodium atoms and two chlorine atoms.

• A compound with one sodium atom and two chlorine atoms.

In the compound NaCl, what is the ratio of sodium to chlorine atoms?

• 2:1

• 2:2

• 1:1

• 1:2

What is the chemical formula for water?

• H2

• HO2

• H2O

• O2H

How many hydrogen atoms are combined with one oxygen atom in a water molecule?

• Four

• Two

• One

• Three