Question

A penny has a mass of 2.50g and the moon has a mass of 7.35 X 10^22

Use this information to answer the questions below. Be sure your answers have the correct number of significant digits.

What is the mass of 1 mole of pennies?

How many moles of pennies have a mass equal to the mass of the moon? Write your answer as a decimal, and round to one place?

Answer 1

Answer:

The mass of 1 mole of pennies is 1.50×10²⁴ g

1.1×10²¹ moles of pennies have a mass equal to the mass of the moon.

Explanation:

As we know, 1 mol = 6.02×10²³ units

Let's think this rule of three:

1 penny weighs 2.50 g

So, 6.02×10²³ pennies would weigh (6.02×10²³  . 2.5) = 1.50×10²⁴ g

We consider that a penny is made of Cu, 100 % Cu.

Let's find out the moles of 1 penny (mass / molar mass)

2.50 g / 63.55 g/mol = 0.0393 moles

Finally we can do this rule of three:

2.50 g are contained in 0.0393 moles of pennies

7.35×10²² g would be contained in (7.35×10²² . 0.0393) / 2.50 = 1.1×10²¹ moles