Question

A brick has a mass of and the Earth has a mass of . 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 bricks? How many moles of bricks have a mass equal to the mass of the Earth?

Answer 1

Complete question

A brick has a mass of 4.0 kg and the Earth has a mass of 6.0 X 10²⁷ g. 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 bricks? Round your answer to 2 significant digits. How many moles of bricks have a mass equal to the mass of the Earth? Round your answer to 2 significant digits.

Answer:

The mass of 1 mole of bricks = 24 X 10²⁶ g (2 significant digits), and

2.5 moles of bricks (2 significant digits) have a mass equal to the mass of the Earth.

Explanation:

Given mass of bricks = 4.0 kg

4.0kg of brick = 4000g

1 mole of any substance always contain  6.022 X 10²³ Avogadro's number

1 mole of bricks contains 6.022 X 10²³ bricks

Therefore, mass of 1 mole of brick = 6.022 X 10²³ X 4000g

= 4000 X 6.022 X 10²³ g

= 24088 X 10²³ g

The mass of 1 mole of bricks = 24 X 10²⁶ g (2 significant digits)

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⇒How many moles of bricks have a mass equal to the mass of the Earth?

Given mass of Earth = 6.0 X 10²⁷ g

24088 X 10²³ g --------> mass of 1 mole of bricks

6.0 X 10²⁷ g --------------> ?

= (6.0 X 10²⁷ g)/(24088 X 10²³ g)

= 2.4909 moles of bricks

≅ 2.5 moles of bricks ( 2 significant digits)

Therefore, 2.5 moles of bricks have a mass equal to the mass of the Earth