Calculate the number of moles of CH3CH2OH in 500ml of the following concentratio

Question

Calculate the number of moles of CH3CH2OH in 500ml of the following concentrations. Ethanol has a density 0.789g/cm3 and a molar mass of 46.1g/mole. a. 70% v/v ______________ b. 1.8 % m/v ______________ Calculate the number of moles of CH3CH2OH in 500ml of the following concentrations. Ethanol has a density 0.789g/cm3 and a molar mass of 46.1g/mole. a. 70% v/v ______________ b. 1.8 % m/v ______________ Calculate the number of moles of CH3CH2OH in 500ml of the following concentrations. Ethanol has a density 0.789g/cm3 and a molar mass of 46.1g/mole. a. 70% v/v ______________ b. 1.8 % m/v ______________

Explanation / Answer

a) 70 % v/v

70 mL CH3CH2OH present in 100 mL solution

70 x 5 mL CH3CH2OH present in 500 mL solution

350 mL CH3CH2OH present

mass = volume x density

mass = 350 x 0.789 = 276.15 g

moles of ethanol = mass / molar mass

moles = 276.15 / 46.1 = 5.99

b) 1.8 % mass /volume

1.8 g ethanol present in 100 mL solution

1.8 x 5 g ethanol present in 500 mL solution

9.0 g ethanol present.

moles = 9.0 / 46.1

moles = 0.19

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