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3 years ago

How do intermolecular forces help explain differences in phase changes (boiling point, melting point)

1 answer:

3 0

Do you mean differences among various substances eg: H2O vs CO2? IMFs determine boiling and melting points by deciding how strongly molecules want to hold on to each other. The strength of IMFs depend on the type of IMFs, eg: dipole-dipole, ion-dipole, induced dipole (London dispersion), etc. Weak IMFs= low boiling point. IMFs also determine many other properties including vapor pressure, etc.

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What is the volume of one mole of any gas at STP?

Vikki [24]

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3 years ago

It has been suggested that the surface melting of ice plays a role in enabling speed skaters to achieve peak performance. Carry

vesna_86 [32]

Explanation:

Relation between pressure, latent heat of fusion, and change in volume is as follows.

$\frac{dP}{dT} = \frac{L}{T \times \Delta V}$

Also, $\frac{L}{T} = \Delta S^{fusion}_{m}$

where, $\Delta V^{fusion}_{m}$ is the difference in specific volumes.

Hence, $\frac{dP}{dT} = \frac{\Delta S^{fusion}_{m}}{\Delta V^{fusion}_{m}}$

As, $\Delta S^{fusion}_{m} = \frac{L}{T} = \frac{6010}{273.15}$ = 22.0 J/mol K

And, $\Delta V^{fusion}_{m} = \frac{M}{d_{H_{2}O}} - \frac{M}{d_{ice}}$ ...... (1)

where, $d_{H_{2}O}$ = density of water

$d_{ice}$ = density of ice

M = molar mass of water = $18.02 \times 10^{-3} kg$

Therefore, using formula in equation (1) we will calculate the volume of fusion as follows.

$\Delta V^{fusion}_{m} = \frac{M}{d_{H_{2}O}} - \frac{M}{d_{ice}}$

= $\frac{18.02 \times 10^{-3}}{997} - \frac{18.02 \times 10^{-3}}{920}$

= $-1.51 \times 10^{-6}$

Therefore, calculate the required pressure as follows.

$\frac{dP}{dT} = \frac{22}{-1.51 \times 10^{-6}}$

= $1.45 \times 10^{7} Pa/K$

or, = 145 bar/K

Hence, for change of 1 degree pressure the decrease is 145 bar and for 4.7 degree change dP = $145 \times 4.7 bar$

= 681.5 bar

Thus, we can conclude that pressure should be increased by 681.5 bar to cause 4.7 degree change in melting point.

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2 years ago

What would happen to a animal cell if it had n\an lysosome?

pantera1 [17]

Honestly I don't know

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2 years ago

If liquid water has a density of 1.00 g/ml at 25 °C and you allow 48 ml of water.to freeze in a 50 ml glass container, will the

tensa zangetsu [6.8K]

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3 years ago

How many grams of water vapor (H2O) are in a 10.2-liter sample at 0.98 atmospheres and 26°C?

diamong [38]

Hey there!

<span>Use the equation of Clapeyron:
</span>
T in kelvin :

26 + 273.15 => 299.15 K

R = 0.082

V = 10.2 L

P = 0.98 atm

number of moles :

P *V = n * R * T

0.98 * 10.2 = n * 0.082 * 299.15

9.996 = n * 24.5303

n = 9.996 / 24.5303

n = 0.4074 moles

Therefore:

Molar mass H2O = 18.01 g/mol

1 mole H2O ------------- 18.01 g
0.4074 moles ----------- m

m = 0.4074 * 18.01 / 1

m = 7.339 g of H2O

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3 years ago