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2 years ago

A gas sample occupies 4.2L at a pressure of 101 kPa. What volume will it occupy if the pressure is increased to 235 kPa

Chemistry

1 answer:

taurus [48]2 years ago

4 0

1.8 L

<h3>Explanation</h3>

The volume of a gas, V, is inversely proportional to the pressure on it, P. That is:

V₁ · T₁ = V₂ · T₂.

Rearranging gives:

V₂ = V₁ · T₁ / T₂ = 4.2 × (101 / 235) = 1.8 L

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Formeaza grafic formarea moleculelor de o2 HCL NH3 se cunoaste O cu Z=8 H cu Z=1 N cu Z=7 Cl cu Z=17

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Grafic O cunoaste penis in throat and hairy ball sacks down my estofogas

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3 years ago

A mysterious white powder could be powdered sugar (C12H22O11), cocaine (C17H21NO4), codeine (C18H21NO3), norfenefrine (C8H11NO2)

rodikova [14]

Norfenefrine (C₈H₁₁NO₂).

<h3>Further explanation</h3>

We will solve a case related to one of the colligative properties, namely freezing point depression.

The freezing point of the solution is the temperature at which the solution begins to freeze. The difference between the freezing point of the solvent and the freezing point of the solution is called freezing point depression.

$\boxed{ \ \Delta T_f = T_f(solvent) - T_f(solution) \ } \rightarrow \boxed{ \ \Delta T_f = K_f \times molality \ }$

<u>Given:</u>

A mysterious white powder could be,

powdered sugar (C₁₂H₂₂O₁₁) with a molar mass of 342.30 g/moles,
cocaine (C₁₇H₂₁NO₄) with a molar mass of 303.35 g/moles,
codeine (C₁₈H₂₁NO₃) with a molar mass of 299.36 g/moles,
norfenefrine (C₈H₁₁NO₂) with a molar mass of 153.18 g/moles, or
fructose (C₆H₁₂O₆) with a molar mass of 180.16 g/moles.

When 82 mg of the powder is dissolved in 1.50 mL of ethanol (density = 0.789 g/cm³, normal freezing point −114.6°C, Kf = 1.99°C/m), the freezing point is lowered to −115.5°C.

<u>Question: </u>What is the identity of the white powder?

<u>The Process:</u>

Let us identify the solute, the solvent, initial, and final temperatures.

The solute = the powder
The solvent = ethanol
The freezing point of the solvent = −114.6°C
The freezing point of the solution = −115.5°C

Prepare masses of solutes and solvents.

Mass of solute = 82 mg = 0.082 g
Mass of solvent = density x volume, i.e., $\boxed{ \ 0.789 \ \frac{g}{cm^3} \times 1.50 \ cm^3 = 1.1835 \ g = 0.00118 \ kg \ }$

We must prepare the solvent mass unit in kg because the unit of molality is the mole of the solute divided by the mass of the solvent in kg.

The molality formula is as follows:

$\boxed{ \ m = \frac{moles \ of \ solute}{kg \ of \ solvent} \ } \rightarrow \boxed{ \ m = \frac{mass \ of \ solute \ (g)}{molar \ mass \ of \ solute \times kg \ of \ solvent} \ }$

Now we combine it with the formula of freezing point depression.

$\boxed{ \ \Delta T_f = K_f \times \frac{mass \ of \ solute \ (g)}{molar \ mass \ of \ solute \times kg \ of \ solvent} \ }$

It is clear that we will determine the molar mass of the solute (denoted by Mr).

We enter all data into the formula.

$\boxed{ \ -114.6^0C - (-115.5^0C) = 1.99 \frac{^0C}{m} \times \frac{0.082 \ g}{Mr \times 0.00118 \ kg} \ }$

$\boxed{ \ 0.9 = \frac{1.99 \times 0.082}{Mr \times 0.00118} \ }$

$\boxed{ \ Mr = \frac{0.16318}{0.9 \times 0.00118} \ }$

We get $\boxed{ \ Mr = 153.65 \ }$

These results are very close to the molar mass of norfenefrine which is 153.18 g/mol. Thus the white powder is norfenefrine.

<h3>Learn more</h3>

The molality and mole fraction of water brainly.com/question/10861444
About the mass and density of ethylene glycol as an antifreeze brainly.com/question/4053884
About the solution as a homogeneous mixture brainly.com/question/637791

Keywords: a mysterious white powder, sugar, cocaine, codeine, norfenefrine, fructose, the solute, the solvent, dissolved, ethanol, normal freezing point, the freezing point depression, the identity

7 0

3 years ago

Read 2 more answers

Bob adds heat to a substance. When enough heat is added, A. its particles move closer together and the substance becomes a gas.

Elena L [17]

Answer:

C. its particles move farther apart and the substance becomes a gas.

Explanation:

A. is wrong because moving closer together creates a solid, not a gas.

B. is wrong because moving father apart creates a gas, not solid.

C. is correct because moving farther apart creates a gas.

D. is wrong because when heat is added particles spread apart because they vibrate faster. Although, in a solid the particles are closer together.

- Just know the states of matter and how the particles move and that will help with this problem.

6 0

2 years ago

a 4.18 g sample of a hydrocarbon is combusted in a bomb calorimeter that contains 974 g of water. the temperature of the water i

lys-0071 [83]

The heat of the reaction, in kJ, when 4.18 g of the hydrocarbon are combusted 775.70 kJ.

The heat energy is given as :

q = m c ΔT + Ccal ΔT

q = ( 974 g× 4.184 ×6.9) + 624 ×6.9

q = 32424.59 J

moles of hydrocarbon = 0.0418 mol

heat of combustion = 32424.59 J / 0.0418 mol

= 775707.89 J

= 775.70 kJ

Thus, A 4.18 g sample of a hydrocarbon is combusted in a bomb calorimeter that contains 974 g of water. the temperature of the water increases by 6.9 °C when the hydrocarbon is combusted. the calorimeter constant for the calorimeter was determined to be 624 J/°C. what is the heat of the reaction is 775.70 kJ.

To learn more about calorimeter here

brainly.com/question/28943378

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5 0

1 year ago

Atmospheric air pressure is measured with a _____.

Svetradugi [14.3K]

It is measured with a barometer

3 0

3 years ago

Read 2 more answers