How To Balance Equations - Part 1

What does the law of conservation of mass state about atoms in a chemical reaction?

• Atoms change their elemental nature.

• Atoms are rearranged but conserved.

• Atoms are destroyed.

• Atoms are created from other elements.

What must remain the same on both sides of a chemical equation?

• The number of molecules

• The types of molecules

• The number of each type of atom

• The physical state of the compounds

How do you balance a chemical equation when the atoms do not initially balance?

• Ignore the imbalance as it is usually minor

• Add catalysts to the reaction

• Adjust the coefficients in front of the compounds

• Change the subscripts in the compounds

In the formula '3 O2', what does the subscript '2' indicate?

• There are two molecules of oxygen.

• There are three oxygen atoms.

• Each molecule has two oxygen atoms.

• The oxygen is doubled in reaction.

If you have two Na2O molecules, how many sodium atoms are there?

• Two sodium atoms

• Six sodium atoms

• Four sodium atoms

• Eight sodium atoms