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
