Question

How many moles of copper are present in 75.0g Cu? Show your complete calculation and give the answer in the correct number of significant digits and with the correct units. Show work.

Answer 1

Answer:

The answer to your question is 1.2 moles of copper

Explanation:

Data

mass of copper = 75 g

moles = ?

Process

1.- Look in the periodic table for the atomic mass of copper.

Atomic mass = 63.55 g/mol

2.- Use proportions to determine the moles of copper in 75 g

                          63.55 g of copper -------------------- 1 mol

                          75 g of copper       --------------------  x

Use cross multiplication

                          x = (75 x 1) / 63.55

                          x = 75 / 63.55

                          x = 1.18 moles ≈ 1.2 moles of copper

Answer 2

Answer:

1.180 moles to 4 significant figures.

Explanation:

From the Periodic Table we see that 1 mole of Copper = 63.546 g

Therefore 75 g of copper = 75/ 63.456

= 1.1802 moles.