A 2.85g sample of an unknown chlorofluorocarbon is decomposed and produces 560mL of chlorine gas at a pressure of 754mmHg and a temperature of 298K .
What is the percent chlorine (by mass) in the unknown chlorofluorocarbon?
PV = nRT calculates n.
Then n = grams/molar mass. You know molar mass and n, calculate grams Cl2.
Then %Cl2 = [grams Cl2/grams sample]*100
Well, it sounds like the chlorofluorocarbon had a bit of a chemical breakdown, which left us with some chlorine gas. Now, to determine the percent chlorine by mass, we'll have to do a little math.
First, let's find out how many moles of chlorine gas we have. To do that, we can 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.
In this case, we have P = 754 mmHg, V = 560 mL (which we can convert to L by dividing by 1000), R = 0.0821 L·atm/(mol·K), and T = 298 K.
Now let's plug those values into the equation and solve for n:
754 mmHg * (560 mL / 1000 mL/L) = n * 0.0821 L·atm/(mol·K) * 298 K
Once you calculate that, you'll find the number of moles of chlorine gas.
Next, we can find the molar mass of chlorine (Cl) by looking it up on the periodic table. It's approximately 35.45 g/mol.
Now, to calculate the mass of chlorine gas, we multiply the molar mass of chlorine by the number of moles of chlorine gas.
Finally, to find the percent chlorine by mass in the unknown chlorofluorocarbon, we can divide the mass of chlorine gas by the initial mass of the sample (2.85 g) and multiply by 100.
So, my friend, grab your calculator and start crunching those numbers. And don't worry, I'll provide a clown nose to keep things light and fun while you work through the calculations. Good luck!
To calculate the percent chlorine (by mass) in the unknown chlorofluorocarbon, you need to determine the mass of chlorine produced from the decomposition of the sample and then calculate its percentage in relation to the mass of the original sample.
Step 1: Calculate the number of moles of chlorine gas produced.
To do this, we need to 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.
Given:
Pressure (P) = 754 mmHg
Volume (V) = 560 mL = 0.560 L (convert mL to L)
Temperature (T) = 298 K
Ideal Gas Constant (R) = 0.0821 L atm/mol K
Using PV = nRT, we can rearrange the equation to solve for n:
n = (PV) / (RT)
n = (754 mmHg * 0.560 L) / (0.0821 L atm/mol K * 298 K)
n = 3.24 x 10^-3 mol
Step 2: Convert moles of chlorine gas to grams.
To do this, we need to use the molar mass of chlorine, which is approximately 35.45 g/mol.
Mass of chlorine gas = number of moles * molar mass
Mass of chlorine gas = 3.24 x 10^-3 mol * 35.45 g/mol
Mass of chlorine gas = 0.115 g
Step 3: Calculate the percent chlorine (by mass) in the unknown chlorofluorocarbon.
The percent chlorine (by mass) can be calculated using the following formula:
% Chlorine = (Mass of chlorine / Mass of sample) * 100
Given: Mass of sample = 2.85 g
% Chlorine = (0.115 g / 2.85 g) * 100
% Chlorine = 4.04%
Therefore, the percent chlorine (by mass) in the unknown chlorofluorocarbon is approximately 4.04%.
To find the percent chlorine (by mass) in the unknown chlorofluorocarbon, we need to calculate the mass of chlorine produced from the decomposition of the chlorofluorocarbon and then divide it by the initial mass of the sample.
First, let's calculate the number of moles of chlorine gas produced. We can 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 (0.0821 L·atm/(mol·K)), and T is the temperature in Kelvin.
Given:
Pressure (P) = 754 mmHg
Volume (V) = 560 mL = 0.560 L
Temperature (T) = 298 K
Convert the pressure from mmHg to atm:
754 mmHg * (1 atm/760 mmHg) = 0.992 atm
Rearranging the ideal gas law equation to solve for n:
n = PV / RT
Substituting the values:
n = (0.992 atm * 0.560 L) / (0.0821 L·atm/(mol·K) * 298 K)
n ≈ 0.0221 mol
Since the decomposition of the chlorofluorocarbon produces one mole of chlorine gas for every mole of chlorofluorocarbon, the number of moles of chlorine is also 0.0221 mol.
Next, let's calculate the molar mass of chlorine (Cl). The molar mass of an element is found on the periodic table, and for chlorine, it is approximately 35.45 g/mol.
Finally, we can calculate the mass of chlorine produced:
Mass of chlorine = number of moles of chlorine * molar mass of chlorine
Mass of chlorine ≈ 0.0221 mol * 35.45 g/mol
Mass of chlorine ≈ 0.782 g
Now, to calculate the percent chlorine (by mass) in the unknown chlorofluorocarbon:
Percent chlorine = (mass of chlorine / initial mass of the sample) * 100
Percent chlorine = (0.782 g / 2.85 g) * 100
Percent chlorine ≈ 27.4%
Therefore, the percent chlorine (by mass) in the unknown chlorofluorocarbon is approximately 27.4%.