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3 years ago

15

why does opening the air valve of a tire at a constant temperature decrease the pressure? A) the temperature decreases B)The vol

ume decreases C)The number of molecules decrease D) The atmospheric pressure decreases

1 answer:

Triss [41]3 years ago

5 0

The answer is B I think

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Practice Problem Website: https://www3.nd.edu/~smithgrp/structure/workbook.html

yarga [219]

6787.67458865446899675566

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3 years ago

If a graduated cylinder's water level reads 50.0 mL, and you add a rock to it so the water level rises to 54.0 mL, what is the v

Ira Lisetskai [31]

The volume of the rock is 4mL

8 0

3 years ago

Please help with this question

Lunna [17]

Answer:

g

Explanation:

4 0

3 years ago

Read 2 more answers

Part a cyclohexane has a freezing point of 6.50 ∘c and a kf of 20.0 ∘c/m. What is the freezing point of a solution made by disso

Andrei [34K]

The mathematical expression for the depression in freezing point is given as:

$\Delta T_{f}= k_{f}m$

where, $\Delta T_{f}$ = depression in freezing point

$k_{f}$ = molal depression constant (20.0 $^{o}Ckg/mole$ )

m = molality

Molality is defined as the ratio of number of moles of solute to the kg of the solvent

Number of moles = $\frac{given mass in g}{molar mass}$

given mass of biphenyl solute = 0.925 g

Molar mass of biphenyl = 154.21 g/mol

Put the values,

number of moles of biphenyl = $\frac{0.925 g}{154.21 g/mol}$

= $0.0059 mole$

Molality = $\frac{number of moles of biphenyl solute}{mass of the solvent in kg}$

Mass of cyclohexane solvent = 25.0 g

Convert g into kg: 1 kg = 1000 g

Thus, mass of cyclohexane = $\frac{25.0}{1000}$

= 0.025 kg

Now, put the values in the formula of molality:

Molality = $\frac{0.0059 mole}{0.025 kg}$

= 0.236 mole/kg or 0.236 m.

Calculate the depression in freezing point:

$\Delta T_{f}= 20.0^{o}C kg/mole\times 0.236 mole/kg$

= $4.72 ^{o}C$

Now, $\Delta T_{f} = T_{solvent} - T_{solution}$

$4.72 ^{o}C = 6.50^{o}C - T_{solution}$

$T_{solution} = 6.50^{o}C- 4.72 ^{o}C$

= $1.78^{o}C$

Hence, freezing point of the solution is $1.78^{o}C$ .

4 0

3 years ago

Read 2 more answers

Cylinders of compressed gas are typically filled to a pressure of 200 bar. For oxygen, what would be the molar volume at this pr

mars1129 [50]

Answer:

a

$V = 0.124 \ Liters$

b

$V = 0.112 \ Liters$

Explanation:

From the question we are told that

The pressure of compressed gas is $P = 200 \ bar = \frac{200}{1.013}= 197.4 \ atm$

The temperature is $T = 25^oC = 25 + 273 = 298 \ K$

Generally the perfect gas equation is mathematically represented as

$PV = nRT$

substituting 0.08206 L-atm/mol-K for R and 1 mole for n

We have that

$V = \frac{1 * 0.08206 * 298 }{ 197.4}$

$V = 0.124 \ Liters$

Generally the van der Waals equation is mathematically represented as

$nRT = [P + \frac{n^2 * a }{V^2 } ][V - nb]$

=> $1 * 0.08206 *298 = [197.4 + \frac{1^2 * 1.364}{V^2 } ][V - 1 * 3.19 * 10^{-2}]$

=> $V = 0.112 \ Liters$

7 0

4 years ago