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3 years ago

A 0.334 g sample of an unknown compound occupies 245 ml at 298 K and 1.22 atm. What is the molar mass of the unknown compound.

Chemistry

1 answer:

marysya [2.9K]3 years ago

6 0

Answer:

27.4 g/mol

Explanation:

Assuming the compound is a gas and that it behaves ideally, we can solve this problem by using the PV=nRT formula, where:

P = 1.22 atm

V = 245 mL ⇒ 245 mL / 1000 = 0.245 L

n = ?

R = 0.082 atm·L·mol⁻¹·K⁻¹

T = 298 K

Inputting the data:

1.22 atm * 0.245 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 298 K

Solving for n:

n = 0.0122 mol

With the calculated number of moles and given mass, we calculate the molar mass:

0.334 g / 0.0122 mol = 27.4 g/mol

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A chemist must prepare 300.0mL of nitric acid solution with a pH of 0.70 at 25°C. He will do this in three steps: Fill a 300.0mL

d1i1m1o1n [39]

Answer: The volume of concentrated solution required is 9.95 mL

Explanation:

To calculate the pH of the solution, we use the equation:

$pH=-\log[H^+]$

We are given:

pH = 0.70

Putting values in above equation, we get:

$0.70=-\log[H^+]$

$[H^+]=10^{-0.70}=0.199M$

1 mole of nitric acid produces 1 mole of hydrogen ions and 1 mole of nitrate ions.

Molarity of nitric acid = 0.199 M

To calculate the volume of the concentrated solution, we use the equation:

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the molarity and volume of the concentrated nitric acid solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted nitric acid solution

We are given:

$M_1=7.0M\\V_1=?mL\\M_2=0.199M\\V_2=350mL$

Putting values in above equation, we get:

$7.0\times V_1=0.199\times 350.0\\\\V_1=\frac{0.199\times 350}{7.0}=9.95mL$

Hence, the volume of concentrated solution required is 9.95 mL

6 0

2 years ago

Read the information about the halogen family.

Elodia [21]

Answer:

See explanation

Explanation:

Chlorine is a member of the halogen family known as a toxic yellowish green gas. Inhalation of chlorine for a prolonged period of time leads to pulmonary edema. If a person comes in contact with compressed liquid chlorine the person may experience frostbite of the skin and eyes.

However chlorine is very useful in water disinfection and is preferred in water treatment because it provides residual disinfection of the treated water.

Chlorine gas may be dissolved in NaOH to form oxochlorate I which is used as a bleach in cleaning.

7 0

3 years ago

A balloon occupies a volume of 2.00 l at 40.0oc. how much volume will it occupy at 30.0oc?

hodyreva [135]

Charles' law says "at a constant pressure, the volume of a fixed amount of gas is directly proportional to its absolute temperature".

V α T

Where V is the volume and T is the temperature in Kelvin of the gas. We can use this for two situations as,
V₁/T₁ = V₂/T₂

V₁ = 2.00 L
T₁ = 40.0 ⁰C = 313 K
V₂ = ?
T₂ = 30.0 ⁰C = 303 K

By applying the formula,
2.00 L / 313 K = V₂ / 303 K
V₂ = (2.00 L / 313 K) x 303 K
V₂ = 1.94 L

Hence, the volume of the balloon at 30.0 ⁰C is 1.94 L

7 0

3 years ago

To what volume would you need to dilute 200 mL of a 5.85M solution of Ca(OH)2 to make it a 1.95M solution?

Blizzard [7]

Answer: 600 mL

Explanation:

Given that;

M₁ = 5.85 m

M₂ = 1.95 m

V₁ = 200 mL

V₂ = ?

Now from the dilution law;

M₁V₁ = M₂V₂

so we substitute

5.85 × 200 = 1.95 × V₂

1170 = 1.95V₂

V₂ = 1170 / 1.95

V₂ = 600 mL

Therefore final volume is 600 mL

8 0

3 years ago

Calculate the vapor pressure of a solution of 32.5 g of glycerol (C3H8O3) in 500.0 g of water at 25°C. The vapor pressure of wat

Luba_88 [7]

The vapor pressure is obtained as 23.47 torr.

<h3>What is the vapor pressure?</h3>

Given that; p = x1p°

p = vapor pressure of the solution

x1 = mole fraction of the solvent

p° = vapor pressure of the pure solvent

Δp = p°(1 - x1)

Δp =x2p°

Δp = vapor pressure lowering

x2 = mole fraction of the of the solute

Number of moles of glycerol = 32.5 g/92 g/mol = 0.35 moles

Number of moles of water = 500.0 g/18 g/mol = 27.8 moles

Total number of moles = 0.35 moles + 27.8 moles = 28.15 moles

Mole fraction of glycerol = 0.35 moles/28.15 moles = 0.012

Mole fraction of water = 27.8 moles/28.15 moles =0.99

Δp = 0.012 * 23.76 torr

Δp = 0.285 torr

p1 = p° - Δp

p1 = 23.76 torr - 0.285 torr

p1 = 23.47 torr

Learn more about vapor pressure:brainly.com/question/14718830

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2 years ago