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3 years ago

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1. Radioactive decay of 40K atoms in an igneous rock has resulted in a ratio of 25 percent 40K atoms to 75 percent 40Ar and 40Ca

atoms. How many years old is this rock?

1 answer:

zhuklara [117]3 years ago

5 0

1/2 of the original parent has decayed, thus one half- life has passed, and the rock is 1.3 billion = 1300 million years old

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How many moles are in 15.5-g SiO2

DochEvi [55]

Answer:

0.26 moles

Explanation:

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Molar mass of SiO2 = 60.08g/mol

Number of moles = 15.5g/60.08g/mol

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4 years ago

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3 years ago

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Dmitrij [34]

It is a mixture

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4 years ago

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 hav

weeeeeb [17]

The given question is incomplete. The complete question is:

A brick has a mass of 4.0 kg and the earth has a mass of $6.0\times 10^{27}g$ 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.

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

Explanation:

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3 years ago

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4 years ago