Ethyl chloride, C 2 H 5 Cl, is used as a local anesthetic. It works by cooling tissue as it vaporizes; its heat of vaporization is 26.4 kJ/mol. How much heat could be removed by 20.0 g of ethyl chloride?
heat = q = mass x dHvap.
q = mols ethyl chloride x dHvap
mols ethyl chloride = grams/molar mass = 20.0/64.5 = approx 0.31
q = 0.31 mol x 26.4 kJ/mol = ? kilojoules.
To calculate the heat that could be removed by 20.0 g of ethyl chloride, you can use the following steps:
Step 1: Convert the given mass of ethyl chloride (20.0 g) to moles.
To do this, we need to know the molar mass of ethyl chloride (C2H5Cl).
The molar mass of carbon (C) is 12.01 g/mol.
The molar mass of hydrogen (H) is 1.01 g/mol.
The molar mass of chlorine (Cl) is 35.45 g/mol.
Now, calculate the molar mass of ethyl chloride:
Molar mass = (2 * molar mass of carbon) + (5 * molar mass of hydrogen) + (1 * molar mass of chlorine)
Molar mass of ethyl chloride = (2 * 12.01 g/mol) + (5 * 1.01 g/mol) + (1 * 35.45 g/mol)
Step 2: Calculate the number of moles of ethyl chloride.
Number of moles = Mass (in grams) / Molar mass
Number of moles = 20.0 g / Molar mass of ethyl chloride
Step 3: Calculate the heat that could be removed.
Heat = Number of moles * Heat of vaporization
Heat = Number of moles * 26.4 kJ/mol
Now, you can plug in the values and calculate the heat that could be removed by 20.0 g of ethyl chloride.
To calculate the amount of heat that can be removed by a given mass of ethyl chloride, we need to use the heat of vaporization and the molar mass.
1. First, we need to find the number of moles of ethyl chloride:
- The molar mass of C2H5Cl is calculated by adding the atomic masses of carbon (C), hydrogen (H), and chlorine (Cl):
- Carbon: 12.01 g/mol
- Hydrogen: 1.008 g/mol
- Chlorine: 35.45 g/mol
- Molar mass of C2H5Cl = (2*12.01) + (5*1.008) + 35.45 = 64.52 g/mol
- Number of moles of ethyl chloride = Given mass of ethyl chloride (in g) / Molar mass of C2H5Cl (in g/mol)
- Number of moles of ethyl chloride = 20.0 g / 64.52 g/mol = 0.310 mol
2. Next, we can calculate the amount of heat that can be removed using the heat of vaporization:
- The heat of vaporization is given as 26.4 kJ/mol.
- Multiplying the number of moles by the heat of vaporization gives us the amount of heat removed:
- Heat removed = Number of moles of ethyl chloride * Heat of vaporization
- Heat removed = 0.310 mol * 26.4 kJ/mol = 8.184 kJ
Therefore, 20.0 g of ethyl chloride can remove 8.184 kJ of heat when it vaporizes.