Chemistry, 10.12.2019 01:31 romaguera06

Determine the vapor pressure of a solution at 25°c that contains 76.6 g of glucose (c6h12o6) in 250.0 ml of water. the vapor pressure of pure water at 25°c is 23.8 torr.70.8 torr7.29 torr72.9 torr22.9 torr23.1 torr

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Answer from: Usman458

The vapor pressure of solution is 23.1 torr

Explanation:

To calculate the mass of water, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of water = 1 g/mL

Volume of water = 250.0 mL

Putting values in above equation, we get:

$1g/mL=\frac{\text{Mass of water}}{250.0mL}\\\\\text{Mass of water}=(1g/mL\times 250.0mL)=250g$

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For glucose:

Given mass of glucose = 76.6 g

Molar mass of glucose = 180.2 g/mol

Putting values in equation 1, we get:

$\text{Moles of glucose}=\frac{76.6g}{180.2g/mol}=0.425mol$

For water:

Given mass of water = 250 g

Molar mass of water = 18 g/mol

Putting values in equation 1, we get:

$\text{Moles of water}=\frac{250g}{18g/mol}=13.9mol$

Mole fraction of a substance is given by:

$\chi_A=\frac{n_A}{n_A+n_B}$

Mole fraction of glucose, $\chi_{(glucose)}=\frac{0.425}{0.425+13.9}=0.030$

As, the relative lowering of vapor pressure is directly proportional to the amount of dissolved solute.

The equation used to calculate relative lowering of vapor pressure follows:

$\frac{p^o-p_s}{p^o}=i\times \chi_{solute}$

where,

$\frac{p^o-p_s}{p^o}$ = relative lowering in vapor pressure

i = Van't Hoff factor = 1 (for non electrolytes)

$\chi_{solute}$ = mole fraction of solute = 0.030

p^o = vapor pressure of pure water = 23.8 torr

p_s = vapor pressure of solution = ?

Putting values in above equation, we get:

$\frac{23.8-p_s}{23.8}=1\times 0.030\\\\p_s=23.1torr$

Hence, the vapor pressure of solution is 23.1 torr

Answer from: Quest

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

Answer from: Quest

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Determine the vapor pressure of a solution at 25°c that contains 76.6 g of glucose (c6h12o6) in 250....