1.) A vapor volume of 1.17 L forms when a sample of liquid CH3CN absorbs 1.00 KJ of heat at its normal boiling point (81.1 C and 1 atm). What is the heat of vaporization in KJ per moles of CH3CN?

2.) The vapor pressure of water at 25 C is 23.76 torr. If a 1.25 g sample of H20 is sealed into an evacuated 1.5 L container, will any liquid be present? If so, what mass of liquid.

For these questions, please describe the steps necessary to complete them. Answers are not necessary.

1) Convert 1.17 L to moles using the ideal gas law at the boiling point T and 1 atm.

n = PV/RT
Divide the absorbed heat by that number of moles, n.

2) Compute tha mass of H2O necessary to fill the volume with 23.76 torr H2O vapor. Use the ideal gas law. If it is less than the mass of H2O present, the rest will be liquid.

thank you very much. my chemistry is very rusty so i need a refresher.

1.) To find the heat of vaporization in KJ per mole of CH3CN, we can use the equation:

q = n * DeltaHvap

where q is the amount of heat absorbed, n is the number of moles of CH3CN, and DeltaHvap is the heat of vaporization.

Step-by-step solution:
1. Convert the given vapor volume from liters to moles:
- Use the ideal gas law equation: PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.
- Rearrange the equation to solve for moles: n = PV/RT.
- Substitute the given values: n = (1 atm * 1.17 L) / (0.0821 atm L/(mol K) * (81.1 + 273.15) K).
- Calculate the value for 'n'.

2. Use the equation q = n * DeltaHvap, where q is the amount of heat absorbed, and 'n' is the number of moles of CH3CN determined in step 1.
3. Rearrange the equation to solve for DeltaHvap: DeltaHvap = q / n.
4. Substitute the given values of 'q' and 'n' into the equation and calculate the value for DeltaHvap.

2.) To determine if any liquid water will be present in the container, we need to compare the vapor pressure of water at 25 °C with the total pressure inside the container. If the vapor pressure is greater than the total pressure inside the container, some liquid water will be present.

Step-by-step solution:
1. Convert the given mass of H2O from grams to moles. You can use the molar mass of water (H2O) to convert grams to moles.
2. Use the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.
3. Rearrange the equation to solve for pressure: P = nRT/V.
4. Substitute the given values of 'n', 'V', and the temperature in Kelvin (25 + 273.15) into the equation and calculate the value for pressure.
5. Compare the calculated pressure from step 4 to the vapor pressure of water at 25 °C (23.76 torr). If the calculated pressure is less than or equal to the vapor pressure, then some liquid water will be present. If the calculated pressure is greater than the vapor pressure, then all the water will be in the gaseous state.

1.) To find the heat of vaporization in KJ per mole of CH3CN, you can use the equation:

q = n * ΔHvap

where q is the heat absorbed, n is the number of moles of CH3CN, and ΔHvap is the heat of vaporization.

To find the number of moles, you can use the ideal gas law:

PV = nRT

Since the sample is at its normal boiling point, the pressure can be assumed to be 1 atm. The temperature should be converted to Kelvin by adding 273.15:

T = 81.1 C + 273.15 = 354.25 K

Now, rearrange the ideal gas law equation to solve for n:

n = PV / RT

Substitute the values you have to find the number of moles.

Once you have the number of moles, you can use the equation:

ΔHvap = q / n

Substitute the given values for q and n to find the heat of vaporization.

2.) To determine if any liquid water will be present in the given conditions, you need to compare the vapor pressure of water at 25 C (23.76 torr) to the pressure inside the container.

First, convert the mass of water to moles. You will need the molecular weight of water (H2O) to do this calculation, which is about 18.015 g/mol.

moles = mass / molecular weight

Substitute the given mass for water to calculate the number of moles.

Next, calculate the molar volume of the container:

molar volume = container volume / moles

Substitute the given container volume and the number of moles to find the molar volume.

Finally, compare the molar volume of the container to the molar volume of water vapor at the given temperature. If the molar volume of water vapor is greater than the molar volume of the container, then no liquid water will be present. But if the molar volume of water vapor is less than the molar volume of the container, some liquid water will be present.