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suter [353]
3 years ago
9

A rock sample contains 4.5g of Potassium-40 and 31.5g of its daughter isotope (Argon-40). How old is the rock sample if Potassiu

m-40 has a half-life of 1.3 billion years?
Chemistry
1 answer:
brilliants [131]3 years ago
8 0
<span>There is a starting mass of 36g of Potassium-40. After 1.3 billion years, there would be 18g of Argon-40. After 2.6 billion years, half of the remaining Potassium-40 would have decayed, leaving 9g of Potassium-40 and giving us 27g of Argon-40. Following this pattern, we see that three half-lives, or 3.9 billion years, have passed. The age of the rock sample is 3.9 billion years.</span>
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Under identical conditions, separate samples of O2 and an unknown gas were allowed to effuse through identical membranes simulta
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Answer:

The molar mass of unknown gas is 145.82 g/mol.

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Effusion rate of unknown gas = R'=\frac{3.86 mL}{t}

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Graham's Law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows the equation:

\text{Rate of diffusion}\propto \frac{1}{\sqrt{\text{Molar mass of the gas}}}

\frac{R}{R'}=\sqrt{\frac{M}{32 g/mol}}

\frac{\frac{8.24 mL}{t}}{\frac{3.86 mL}{t}}=\sqrt{\frac{M}{32 g/mol}}

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3 0
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What is the answer??
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For the future, you might want to look at some videos to help you! :) (Tyler DeWitt is a really good chem you-tube teacher!)


7 0
3 years ago
Read 2 more answers
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