2. Atoms & Elements

If a sample of sodium chloride, NaCl, contains 73.1 kg, what is its number of formula units?

Calculate the number of oxygen atoms found in 783.9 g NiCl₂ • 6 H₂O.

If the density of water is 1.00 g/mL at 25°C, calculate the number of water molecules found in 1.50 x 10³ µL of water.

A cylindrical copper wire is used for the fences around a house. The copper wire has a diameter of 0.0750 in. How many copper atoms are found in 5.160 cm piece? The density of copper is 8.96 g/cm³. (V = π • r² • h)

How many atoms of oxygen are in the chemical formula 2Ca(ClO₂)₂? 2, 4, 6, or 8?

How many moles are there in 8.50 x 10^24 molecules of sodium sulfate, Na₂SO₃?

How many moles are in 2.5 g of N₂? 0.089 moles, 0.18 moles, 1.3 moles, 11 moles

What is the number of moles of CO₂ in a 220 gram sample of CO₂?