A volume of gas at 1.01 atm was measured at 236 mL . What will be the volume if the pressure is

When of a certain molecular compound X are dissolved in of benzene , the freezing point of the solution is measured to be . Calc

puteri [66]

The question is incomplete. Here is the complete question.

When 2.10 g of a certain molecular compound X are dissolved in 65.0 g of benzene (C₆H₆), the freezing point of the solution is measured to be 3.5°C. Calculate the molar mass of X. If you need any additional information on benzene, use only what you find in the ALEKS Data resource. Also, be sure your answer has a unit symbol, and is rounded to 2 significant digits.

Answer: MM = 47.30 g/mol.

Explanation: There is a relationship between freezing point depression and molality. With this last one, is possible to calculate molar mass or molar weight of a compound.

Freezing Point Depression occurs when a solute is added to a solvent: the freezing point of the solvent decreases when a non-volatile solute is incremented.

Molality or molal concentration is a quantity of solute dissolved in a certain mass, in kg, of solvent. Its symbol is m and it's defined as

$m=\frac{moles(solute)}{kg(solvent)}$

Freezing point depression and molal are related as the following:

$\Delta T_{f}=K_{f}.m$

where

$\Delta T_{f}$ is freezing point depression of solution

$K_{f}$ is molal freezing point depression constant

m is molality

Now, to determine molar mass, first, find molality of the mixture:

$\Delta T_{f}=K_{f}.m$

$m=\frac{\Delta T_{f}}{K_{f}}$

For benzene, constant is 5.12°C/molal. Then

$m=\frac{3.5}{5.12}$

m = 0.683 molal

Second, knowing the relationship between molal and moles of solute, determine the last one:

$m=\frac{moles(solute)}{kg(solvent)}$

$mol(solute)=m.kg(solvent)$

mol(solute) = 0.683(0.065)

mol(solute) = 0.044 mol

The definition for Molar mass is the mass in grams of 1 mol of substance:

$n(moles)=\frac{m(g)}{MM(g/mol)}$

$MM=\frac{m}{n}$

In the mixture, there are 0.044 moles of X, so its molecular mass is

$MM=\frac{2.1}{0.044}$

MM = 47.30 g/mol

The molecular compound X has molecular mass of 47.30 g/mol.

7 0

3 years ago

True or false? The empirical formula of a compound is the simplest formula that shows the numerical relationship of the elements

Delicious77 [7]

Answer:

True

Explanation:

I think it’s true because the empirical formula of a compound is actually the simplest formula that shows the numerical relationship of the elements in the compound.

hop that helps!

7 0

3 years ago

Read 2 more answers

A 1.87 mol sample of Ar gas is confined in a 45.5 liter container at 23.6 °C.

lora16 [44]

Answer:

a. increase

Explanation:

Based on the kinetic molecular theory of gases, the average kinetic energy of the system will increase.

The average kinetic energy is heat
If temperature increases, heat of a system will also rise.
According the kinetic molecular theory "the temperature of the gas is a measure of the average kinetic energy of the molecules"

Therefore, due to the increase in temperature, the average kinetic energy of the system increases.

5 0

3 years ago

What does two bonded flurione atoms form?

Archy [21]

2 Fluorine atoms covalently bonded with each other, each sharing an equal number of a single, one valence electron to achieve a stable octet, would form a diatonic fluorine gas. It is a diatomic molecule, a molecule consisting of 2 atoms that are the same, in this case fluorine.

8 0

3 years ago

Using a chemical equation to find moles of product from moles...

kaheart [24]

Answer: 0.600 moles

Balanced eqn for decomposition of the rocket fuel:

2 NH4ClO4 (s) ----> N2 (g) + Cl2 (g) + 2 O2 (g) + 4 H2O (g)

Since, 2 moles of NH4ClO4 produces 2 moles of O2 gas, this means that 0.6 moles of NH4ClO4 will produce 0.6 moles of O2 gas

7 0

2 years ago