- #1

lioric

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## Homework Statement

20g of saturated solution of potassium nitrate is cooled from 68 to 36 degree Celsius

What is the mass of potassium nitrate which crystallizes?

Potassium nitrate solubility per 100g of water

68 degree Celsius = 120g

38 degree Celsius = 60g

## Homework Equations

I tried without equations just cross multiplying

## The Attempt at a Solution

Please check if my answer is correct

Since the question says 20g of solution which means it's mass of potassium nitrate + water

So since

120g = 100g water = 220g solution (120+100)

120g = 220g

X = 20g

X= 10.9g of potassium nitrate in unknown amount of water

20-10.9= 9.1g of water

Therefore 20g of solution is actually 10.9g of potassium nitrate in 9.1g of water at 68 degree Celsius

In 38 degree Celsius = 60g potassium nitrate per 100 g of water

So

60g = 100g

X = 9.1g

X = 5.46g potassium nitrate in 38 degree Celsius in 9.1g water

Amount of potassium nitrate crystallized

10.9-5.46=5.44

Is this calculation correct?

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