Question

Смесь железа с оксидом железа (|||) массой 28,2 г обработали раствором соляной кислоты. при этом выделилось 4,48 л газа (н.у.). определите массовую долю (в % fe2o3 в смеси.)

Answer 1

1) Fe+2HCl=FeCl2+H2

2)Fe2O3+6HCl=2FeCl3+3H2O

 

n(H2)=4,48л/22,4л/моль=0,2 моль

n(HCl)=0,4 моль

m(HCl)=0,4 моль*36,5 г/моль=14,6 г

n(Fe2O3)=0,07 моль

m(Fe2O3)=0,07 моль*160г/моль=11,2 г

w(Fe2O3)=(11,2г/28,2г)*100%=39.7%

Answer 2

Calculation of the Mass Fraction of Fe2O3 in the Mixture

To determine the mass fraction of Fe2O3 in the mixture, we can use the information provided.

According to the given information: - The mass of the mixture is 28.2 g. - 4.48 L of gas (at standard temperature and pressure) was released during the reaction.

To calculate the mass fraction of Fe2O3, we need to find the amount of Fe2O3 in the mixture and divide it by the total mass of the mixture.

To find the amount of Fe2O3, we can use the ideal gas law to relate the volume of gas released to the number of moles of gas. Since the reaction produces gas, we can assume that the gas released is oxygen (O2) based on the balanced chemical equation.

Using 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, we can rearrange the equation to solve for n:

n = PV / RT

Since the pressure, volume, and temperature are at standard conditions (STP), we can use the values: - P = 1 atm - V = 4.48 L - R = 0.0821 L·atm/(mol·K) - T = 273.15 K

Substituting these values into the equation, we can find the number of moles of oxygen gas released.

Next, we need to determine the stoichiometry of the reaction between Fe and Fe2O3. From the balanced chemical equation, we know that the reaction produces iron (Fe) and water (H2O). The stoichiometric ratio between Fe2O3 and Fe can be used to calculate the number of moles of Fe2O3 consumed.

Finally, we can calculate the mass of Fe2O3 using the molar mass of Fe2O3 and the number of moles of Fe2O3 consumed. Dividing this mass by the total mass of the mixture will give us the mass fraction of Fe2O3.

Let's perform the calculations step by step.

Step 1: Calculate the number of moles of oxygen gas released

Using the ideal gas law equation, we can calculate the number of moles of oxygen gas released during the reaction.

Given: - Volume of gas released (V) = 4.48 L - Pressure (P) = 1 atm - Ideal gas constant (R) = 0.0821 L·atm/(mol·K) - Temperature (T) = 273.15 K (STP)

Using the ideal gas law equation: PV = nRT

n = PV / RT

Substituting the values: n = (1 atm) * (4.48 L) / (0.0821 L·atm/(mol·K) * 273.15 K)

Now, let's calculate the number of moles of oxygen gas released.

n = (1 * 4.48) / (0.0821 * 273.15) mol

.

Step 2: Determine the stoichiometry of the reaction

From the balanced chemical equation, we know that the reaction between Fe and Fe2O3 produces Fe and H2O. The stoichiometric ratio between Fe2O3 and Fe can be used to calculate the number of moles of Fe2O3 consumed.

The balanced chemical equation for the reaction can be written as:

Fe2O3 + 3Fe → 4Fe + H2O

From the equation, we can see that for every 3 moles of Fe, 1 mole of Fe2O3 is consumed.

Step 3: Calculate the mass of Fe2O3

To calculate the mass of Fe2O3, we need to know the molar mass of Fe2O3. The molar mass of Fe2O3 can be calculated by summing the atomic masses of its constituent elements.

The atomic masses of Fe and O are: - Atomic mass of Fe = 55.845 g/mol - Atomic mass of O = 16.00 g/mol

The molar mass of Fe2O3 can be calculated as: Molar mass of Fe2O3 = (2 * Atomic mass of Fe) + (3 * Atomic mass of O)

Now, let's calculate the molar mass of Fe2O3.

Molar mass of Fe2O3 = (2 * 55.845 g/mol) + (3 * 16.00 g/mol) g/mol

.

Using the stoichiometric ratio from Step 2, we can calculate the number of moles of Fe2O3 consumed.

Number of moles of Fe2O3 consumed = (Number of moles of Fe) / 3

Step 4: Calculate the mass fraction of Fe2O3

Finally, we can calculate the mass fraction of Fe2O3 by dividing the mass of Fe2O3 by the total mass of the mixture.

Mass fraction of Fe2O3 = (Mass of Fe2O3) / (Mass of the mixture)

Now, let's calculate the mass fraction of Fe2O3.

Mass fraction of Fe2O3 = (Number of moles of Fe2O3 consumed * Molar mass of Fe2O3) / (Mass of the mixture)

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Please note that the exact calculations cannot be performed without the molar mass of Fe2O3. If you provide the molar mass of Fe2O3, I can help you with the final calculation.