Water freezes at___

A solution contains 5.25 g of urea, CO(NH2)2 (a nonvolatile solute) and 0.100 kg of water. If the vapor pressure of pure water a

babymother [125]

Answer:

The vapor pressure of the solution is 23.3 torr

Explanation:

Step 1: Data given

Mass of urea = 5.25 grams

Mass of water = 0.100 kg = 100 grams

Temperature = 25.0 °C

Vapor pressure of water = 23.7 torr

Step 2: Calculate moles of water

Moles H2O = mass H2O / molar mass H2O

Moles H2O = 100 grams / 18.02 g/mol

Moles H2O = 5.55 moles

Step 3: Calculate moles of urea

Moles urea = 5.25 grams / 60.06 g/mol

Moles urea = 0.0874 moles

Step 4: Calculate mol fraction H2O

Mol fraction H2O = 5.55 moles / (5.55 + 0.0874)moles

Mol fraction H2O = 0.984

Step 5: calculate the vapor pressure of the solution

This means that you can use the mole fraction of water and the vapor pressure of pure water at 25° C to determine the vapor pressure of the solution.

Psol =Xwater * Pwater

⇒Psol = the vapor pressure of the solution

⇒Xwater =the mol fraction of water

⇒Pwater = the vapor pressure of pure water

Psol = 0.984 * 23.7 torr

Psol = 23.3 torr

The vapor pressure of the solution is 23.3 torr

3 0

4 years ago

What volume (in mL) of concentrated HCl (12 M) is needed to make 1500 mL of a 3.5 M solution?

Monica [59]

Don’t like the link it’s dangerous and reply to my comment to i can help you :)

7 0

3 years ago

PLEASE HELP FAST!!!!!!!!!!!!!<br><br> Define erosion.

ziro4ka [17]

<span>the process of eroding or being eroded by wind, water, or other natural agents. Hope this
helps.

</span>

3 0

4 years ago

Read 2 more answers

What characterizes a homogeneous mixture?

weqwewe [10]

A homogeneous mixture is uniform throughout, like water that has dissolved gases. You cannot easily distinguish the individual parts of the mixture. Many other drinks are considered homogeneous too. Laundry detergent and colognes are other examples of homogeneous mixtures. Homogeneous mixtures can also be a solid (ie. steel), liquid or gas form. It does not always have to be a liquid.

4 0

3 years ago

A solution was prepared by dissolving 195.0 g of KCl in 215 g of water. Calculate the mole fraction of KCl. (The formula weight

defon

Answer:

Approximately $0.180$ .

Explanation:

The mole fraction of a compound in a solution is:

$\displaystyle \frac{\text{Number of moles of compound in question}}{\text{Number of moles of all particles in the solution}}$ .

In this question, the mole fraction of $\rm KCl$ in this solution would be:

$\displaystyle X_\mathrm{KCl} = \frac{n(\mathrm{KCl})}{n(\text{All particles in this soluton})}$ .

This solution consist of only $\rm KCl$ and water (i.e., $\rm H_2O$ .) Hence:

$\begin{aligned} X_\mathrm{KCl} &= \frac{n(\mathrm{KCl})}{n(\text{All particles in this soluton})}\\ &= \frac{n(\mathrm{KCl})}{n(\mathrm{KCl}) + n(\mathrm{H_2O})}\end{aligned}$ .

From the question:

Mass of $\rm KCl$ : $m(\mathrm{KCl}) = 195.0\; \rm g$ .
Molar mass of $\rm KCl$ : $M(\mathrm{KCl}) = 74.6\; \rm g \cdot mol^{-1}$ .

Mass of $\rm H_2O$ : $m(\mathrm{H_2O}) = 215\; \rm g$ .
Molar mass of $\rm H_2O$ : $M(\mathrm{H_2O}) = 18.0\; \rm g\cdot mol^{-1}$ .

Apply the formula $\displaystyle n = \frac{m}{M}$ to find the number of moles of $\rm KCl$ and $\rm H_2O$ in this solution.

$\begin{aligned}n(\mathrm{KCl}) &= \frac{m(\mathrm{KCl})}{M(\mathrm{KCl})} \\ &= \frac{195.0\; \rm g}{74.6\; \rm g \cdot mol^{-1}} \approx 2.61\; \em \rm mol\end{aligned}$ .

$\begin{aligned}n(\mathrm{H_2O}) &= \frac{m(\mathrm{H_2O})}{M(\mathrm{H_2O})} \\ &= \frac{215\; \rm g}{18.0\; \rm g \cdot mol^{-1}} \approx 11.9\; \em \rm mol\end{aligned}$ .

The molar fraction of $\rm KCl$ in this solution would be:

$\begin{aligned} X_\mathrm{KCl} &= \frac{n(\mathrm{KCl})}{n(\text{All particles in this soluton})}\\ &= \frac{n(\mathrm{KCl})}{n(\mathrm{KCl}) + n(\mathrm{H_2O})} \\ &\approx \frac{2.61 \; \rm mol}{2.61\; \rm mol + 11.9\; \rm mol} \approx 0.180\end{aligned}$ .

(Rounded to three significant figures.)

8 0

3 years ago

Water freezes at____.