Question

1)рассчитайте массовую долю хлора в газовой смеси содержащий хлор водород и азот объемы которых при н.у. соответственно 2,24 дм3, 4,48 дм3 и 4,48 дм32)через раствор калий-иодида пропустили 2,24 дм3 воздуха с примесью хлора. В результате реакции образовался иод массой 0,12 г. определите объемную долю хлора в воздухе

Answer 1

1) По условию: V(Cl2)=2,24 л; V(H2)=4,48 л; V(N2)=4,48 л
Надо найти массу каждого газа в смеси, для этого используется такая формула: m=V/Vm * M, где m-масса газа, V- его объем, Vm - молярный объем (=22,4л), M - молярная масса газа. 

M(Cl2)=35,5*2=71; М(H2)=1*2=2; М(N2)=14*2=28
m(Cl2)=2,24/22,4 * 71= 7,1 г; 
m(H2)=4,48/22,4 * 2= 0,4 г; 
m(N2)=4,48/22,4 * 28= 5,6 г.

Далее используем эту формулу:  w(в-ва)=m(в-ва)/m(р-ра), где w(в-ва)- массовая доля в-ва, m(в-ва)- масса этого в-ва, m(р-ра) - масса р-ра (смеси), в котором это в-во находится. w(Cl2)= 7,1/(7,1+0,4+5,6)= 7,1/13,1 = 0,542 ; 54,2%

2) 2KI + Cl2 --> 2KCl + I2
n(I2)=0,12/(127*2)= 0,12/254 = 0,000472 моль
тогда по уравнению n(Cl2)=n(I2)=0,000472 моль
V(Cl2)=0,000472*22,4=0,0106 л
объемная доля(Cl2)= 0,0106/22,4=0,000472; 0,0472%

Answer 2

Calculation of Chlorine Mass Fraction in Gas Mixture

To calculate the mass fraction of chlorine in a gas mixture containing chlorine, hydrogen, and nitrogen, we need to know the volumes of each gas at standard conditions (n.u.). The volumes given are 2.24 dm³, 4.48 dm³, and 4.48 dm³ for chlorine, hydrogen, and nitrogen, respectively.

To calculate the mass fraction of chlorine, we can use the ideal gas law, which states that the number of moles of a gas is directly proportional to its volume at constant temperature and pressure. The mass fraction of chlorine can be calculated by dividing the mass of chlorine by the total mass of the gas mixture.

To determine the mass of chlorine, we need to know the molar mass of chlorine. The molar mass of chlorine (Cl₂) is approximately 70.906 g/mol.

Let's calculate the mass fraction of chlorine in the gas mixture:

1. Calculate the number of moles of each gas: - Moles of chlorine (Cl₂): 2.24 dm³ * (1 mol/22.414 dm³) = 0.1 mol [[1]] - Moles of hydrogen (H₂): 4.48 dm³ * (1 mol/22.414 dm³) = 0.2 mol [[1]] - Moles of nitrogen (N₂): 4.48 dm³ * (1 mol/22.414 dm³) = 0.2 mol [[1]]

2. Calculate the mass of chlorine: - Mass of chlorine = Moles of chlorine * Molar mass of chlorine - Mass of chlorine = 0.1 mol * 70.906 g/mol = 7.091 g

3. Calculate the total mass of the gas mixture: - Total mass of the gas mixture = Mass of chlorine + Mass of hydrogen + Mass of nitrogen - Total mass of the gas mixture = 7.091 g + (0.2 mol * 2.016 g/mol) + (0.2 mol * 28.013 g/mol) - Total mass of the gas mixture = 7.091 g + 0.403 g + 5.603 g = 13.097 g

4. Calculate the mass fraction of chlorine: - Mass fraction of chlorine = (Mass of chlorine / Total mass of the gas mixture) * 100% - Mass fraction of chlorine = (7.091 g / 13.097 g) * 100% = 54.0%

Therefore, the mass fraction of chlorine in the gas mixture is approximately 54.0%.

Calculation of Chlorine Volume Fraction in Air

To determine the volume fraction of chlorine in air, we need to know the volume of air and the mass of iodine formed during the reaction.

The volume of air given is 2.24 dm³, and the mass of iodine formed is 0.12 g.

To calculate the volume fraction of chlorine in air, we can use the stoichiometry of the reaction between chlorine and potassium iodide. The balanced equation for the reaction is:

2 KI + Cl₂ → 2 KCl + I₂

From the balanced equation, we can see that 1 mole of chlorine reacts with 2 moles of potassium iodide to produce 1 mole of iodine.

Let's calculate the volume fraction of chlorine in air:

1. Calculate the number of moles of iodine formed: - Moles of iodine = Mass of iodine / Molar mass of iodine - Moles of iodine = 0.12 g / 253.808 g/mol = 0.000472 mol

2. Calculate the number of moles of chlorine: - Moles of chlorine = Moles of iodine / 1 (from the balanced equation) - Moles of chlorine = 0.000472 mol

3. Calculate the volume of chlorine in air: - Volume of chlorine = Moles of chlorine * Molar volume at n.u. - Volume of chlorine = 0.000472 mol * 22.414 dm³/mol = 0.0106 dm³

4. Calculate the volume fraction of chlorine in air: - Volume fraction of chlorine = (Volume of chlorine / Volume of air) * 100% - Volume fraction of chlorine = (0.0106 dm³ / 2.24 dm³) * 100% = 0.473%

Therefore, the volume fraction of chlorine in air is approximately 0.473%.

Please note that these calculations are based on the information provided and assumptions made.