Question

При сгорании 25 мл смеси метана, угарного газа и пропана получили 37 мл углекислого газа. Вычислить объем пропана в исходной смеси, н.у

Answer 1

Запишем уравнения протекающих реакций:

CH4 + 2O2 = CO2 + 2H2O

2CO + O2 = 2CO2

C3H8 + 5O2 = 3CO2 + 4H2O

Пусть в реакций вступеют:

х литров CH4

y литров CO

z литров C3H8

По уравнениям реакций:

V(CO2 в реакции с CH4) = V(CH4) = x л

V(CO2 в реакции с CO) = V(CO) = yл

V(CO2 в реакции с C3H8) = 3V(C3H8) = 3zл

Эти утверждения основаны на том, что условия при которых измерялись объемы газов нормальные

Составим два уравнения:

х + у + 3z = 37мл

х + у + z = 25мл

Вычтем из первого уравнения второе и получим:

2z = 12

z = 6мл

zмл - объем пропана, по условию решения

Ответ: 6мл

 

Answer 2

Calculating the Volume of Propane in the Initial Mixture

To calculate the volume of propane in the initial mixture, we can use the information provided about the volumes of the gases produced during the combustion.

Given: - Volume of the mixture burned (V_total) = 25 ml - Volume of carbon dioxide produced (V_CO2) = 37 ml

We need to find the volume of propane in the initial mixture.

Using the Chemical Equation for Combustion

The balanced chemical equation for the combustion of propane is: C3H8 + 5O2 → 3CO2 + 4H2O

From the equation, we can see that 1 mole of propane (C3H8) produces 3 moles of carbon dioxide (CO2).

Calculating the Moles of Carbon Dioxide Produced

First, we need to convert the volume of carbon dioxide produced to moles. To do this, we can use the molar volume of a gas at standard temperature and pressure (STP), which is 22.4 L/mol or 22.4 dm^3/mol.

Given: - Volume of carbon dioxide produced (V_CO2) = 37 ml

Converting the volume to liters: 37 ml = 0.037 L

Now, we can calculate the moles of carbon dioxide produced: Moles of CO2 = Volume of CO2 / Molar volume at STP Moles of CO2 = 0.037 L / 22.4 L/mol Moles of CO2 ≈ 0.00165 moles

Calculating the Moles of Propane

Since 1 mole of propane produces 3 moles of carbon dioxide, the moles of propane can be calculated using the moles of carbon dioxide produced.

Moles of propane = Moles of CO2 / 3 Moles of propane ≈ 0.00165 moles / 3 Moles of propane ≈ 0.00055 moles

Converting Moles to Volume

Now, we can convert the moles of propane to volume using the molar volume at STP.

Volume of propane = Moles of propane * Molar volume at STP Volume of propane ≈ 0.00055 moles * 22.4 L/mol Volume of propane ≈ 0.01232 L

Therefore, the volume of propane in the initial mixture is approximately 0.01232 liters.