Counting Atoms in Chemical Equations

What does the law of conservation of matter state?

• Matter can be created and destroyed.

• Matter can only be created, not destroyed.

• Matter can neither be created nor destroyed, only transformed.

• Matter can only be destroyed, not created.

In a chemical reaction, what happens to the atoms involved?

• Atoms rearrange without being created or destroyed.

• Atoms are created.

• Atoms disappear.

• Atoms are destroyed.

How do you ensure the number of atoms is conserved in a chemical equation?

• Change the coefficients.

• Change the subscripts.

• Only count the reactants.

• Ignore the hydrogen atoms.

What does the subscript in a chemical formula indicate?

• Number of reactions.

• Number of atoms of each element in a molecule.

• Total number of elements.

• Number of molecules.

How many atoms of hydrogen are present in three molecules of hydrogen gas (3H₂)?

• Twelve

• Nine

• Six

• Three

What is the total number of oxygen atoms in two molecules of rust (2Fe₂O₃)?

• Two

• Four

• Six

• Eight

How many iron atoms are there in one molecule of rust (Fe₂O₃)?

• Six

• Four

• Three

• Two

If you have four molecules of water (4H₂O), how many oxygen atoms do you have?

• Six

• Two

• Eight

• Four

2C₆H₁₂O₆

How many carbon atoms are present?

• Twenty-four

• Eighteen

• Twelve

• Six

What is the correct calculation to find the number of hydrogen atoms in two molecules of sugar (2C₆H₁₂O₆)?

• 6 x 1

• 6 x 2

• 12 x 2

• 12 x 1