Learning Module 32: Compositional Stoichiometry

How many atoms are there in a 2 moles of oxygen atoms? How many atoms are there in 2 moles of oxygen molecules?

12 x 1023 and 24 x 1023

How many grams of carbon are in 12 x 1023 atoms of carbon?

24

If there are 12 x 1023 oxygens in a sample of water, how many grams of hydrogen are in the sample?

4 grams

What percentage of the mass of hydrofluoric acid (HF) is contributed by hydrogen? Hint: what is the molar mass of hydrofluoric acid?

5%

How many grams of oxygen are in a sample of carbon dioxide (CO2) that has 24 grams of C?

64 grams

Why is it possible to do compositional stoichiometry problems in your head?

All of the above

What mathematical tool do we use to determine the ratio of elements in a compound?

Stoichiometry

Diatomic elements are important. What makes them different from other elemental substances?

The atoms are found in pairs in nature.