Questions: Molecules and Reading Chemical Formulas
3 questions to test your understanding
Score: 0 / 3
Question 1 Multiple Choice
How many total atoms are in one molecule of glucose, C6H12O6?
A6
B12
C18
D24
Count each element's subscript: 6 carbon atoms + 12 hydrogen atoms + 6 oxygen atoms = 24 total atoms per glucose molecule.
Question 2 True / False
In the formula CO2, the subscript 2 means there are two carbon atoms.
TTrue
FFalse
Answer: False
The subscript 2 in CO2 applies to the oxygen, not the carbon. The formula means one carbon atom bonded to two oxygen atoms. Carbon has no subscript, which means there is exactly one carbon atom.
Question 3 Short Answer
Write the number of each type of atom in a molecule of ammonia, NH3.
Think about your answer, then reveal below.
Model answer: 1 nitrogen atom and 3 hydrogen atoms.
In the formula NH3, the N has no subscript, so there is 1 nitrogen atom. The H has a subscript of 3, meaning there are 3 hydrogen atoms. A molecule of ammonia therefore contains 4 atoms in total.