Formulae

The video tutorial explains the composition of compounds, highlighting that compounds consist of atoms combined in a specific fixed ratio. It provides examples such as sodium chloride (NaCl), which has a 1:1 ratio of sodium to chlorine atoms, and water (H2O), which consists of two hydrogen atoms and one oxygen atom.

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

• They consist of atoms in a random ratio.

• They consist of atoms in a fixed ratio.

• They consist of atoms in a variable ratio.

• They consist of atoms in a changing ratio.

Which of the following is the correct chemical formula for sodium chloride?

• Na2Cl2

• Na2Cl

• NaCl2

• NaCl

In the compound NaCl, how many sodium atoms are there for each chlorine atom?

• One sodium atom

• Three sodium atoms

• Four sodium atoms

• Two sodium atoms

What is the chemical formula for water?

• H2O

• OH2

• HO2

• H2O2

How many hydrogen atoms are present in a single water molecule?

• Three hydrogen atoms

• Two hydrogen atoms

• One hydrogen atom

• Four hydrogen atoms