Question

A solution contains $20$% solute by weight at ${60}^{o}C$. Whencooled to ${30}^{o}C$, the solution contains $10$% solute by weight. When $45g$ solution is cooled from ${60}^{o}C$ to ${30}^{o}C$, the mass of solute deposited is:

Answer 1

Solution contain 20% of solute by weight at $60^{o}C$

Solution contain 10% of solute by weight at $30^{o}C$

When the 45g solution is cooled from $60^{o}C$ to $30^{o}C$

the mass of solute deposited are

$=45g\times \frac{20}{100}\left(at60^{o}C\right)$

$=4.5\times 2$

$=9g$

$=45g\times \frac{10}{100}\left(at30^{o}C\right)$

$=4.5\times 1$

$=4.5g$

$\therefore$ At $60^{o}C$ mass of solute is 9g

And at $30^{o}C$ mass of solute is 4.5g.