The molality of calcium chloride (CaCl2) in an aqueous solution is 2.46 m. What is mole fraction of the solute?

Chemistry

1 answer:

zysi [14]4 years ago

4 0

Given that CaCl2 = 2.46 m

Therefore 2.46 mole of CaCl2 present in 1.00 g of solution

Mass of 2.46 mole CaCl2= number of mole * molar mass

= 2.46 mole * 110.98 g/mol

= 273.01 g

Mass of water or solvent = mass of solution – mass of solute

= 1000 g -273.01 g

= 726.99 g

Mole of water = amount in g / molar mass

= 726.99 g/18.02 g/ mole

= 40.34 moles

Mole fraction of CaCl2 = number of mole of CaCl2 / total moles

= 2.46 /2.46+40.34

= 2.46/42.8

= 0.057

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3. A 31.2-g piece of silver (s = 0.237 J/(g · °C)), initially at 277.2°C, is added to 185.8 g of a liquid, initially at 24.4°C,

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In this case, since silver is initially hot as it cools down, the heat it loses is gained by the liquid, which can be thermodynamically represented by:

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$m_{Ag}Cp_{Ag}(T_2-T_{Ag})=-m_{liquid}Cp_{liquid}(T_2-T_{liquid})$

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