Question

Образец порошка железа массой 0,32 г при обработке кислотой вытеснил 0,112 л водорода. Какова массовая доля (%) железа в образце?

Answer 1

Обозначим кислоту HX.

Fe+2HX-->FeX2+H2↑

n(H2)=V(H2)/Vm=0,112л/22,4л/моль=0,005 моль=n(Fe)
m(Fe)=n*M=0,005моль*56г/моль=0,28 г
w(Fe)=0,28г/0,32г=0,875 (87,5%)

Answer 2

Calculation of the Iron Content in the Sample

To determine the mass percentage of iron in the sample, we need to use the information provided. The sample of iron powder with a mass of 0.32 g reacts with an acid to produce 0.112 L of hydrogen gas.

To calculate the mass percentage of iron in the sample, we can use the following formula:

Mass Percentage of Iron = (Mass of Iron / Mass of Sample) x 100

First, we need to calculate the mass of iron in the sample. We can do this by using the molar volume of hydrogen gas at standard temperature and pressure (STP), which is 22.4 L/mol. Since 1 mole of iron reacts with 1 mole of hydrogen gas according to the balanced chemical equation, we can calculate the number of moles of hydrogen gas produced:

Number of Moles of Hydrogen Gas = Volume of Hydrogen Gas / Molar Volume of Hydrogen Gas at STP

Using the given volume of hydrogen gas (0.112 L) and the molar volume of hydrogen gas at STP (22.4 L/mol), we can calculate the number of moles of hydrogen gas produced.

Next, we can use the stoichiometry of the balanced chemical equation to determine the number of moles of iron in the sample. Since 1 mole of iron reacts with 1 mole of hydrogen gas, the number of moles of iron is equal to the number of moles of hydrogen gas.

Finally, we can calculate the mass of iron in the sample using the molar mass of iron (55.845 g/mol) and the number of moles of iron.

Now, let's calculate the mass percentage of iron in the sample using the formula mentioned earlier.

Calculation Steps:

1. Calculate the number of moles of hydrogen gas: - Number of Moles of Hydrogen Gas = Volume of Hydrogen Gas / Molar Volume of Hydrogen Gas at STP - Number of Moles of Hydrogen Gas = 0.112 L / 22.4 L/mol

2. Calculate the number of moles of iron: - Number of Moles of Iron = Number of Moles of Hydrogen Gas

3. Calculate the mass of iron in the sample: - Mass of Iron = Number of Moles of Iron x Molar Mass of Iron

4. Calculate the mass percentage of iron in the sample: - Mass Percentage of Iron = (Mass of Iron / Mass of Sample) x 100

Calculation Results:

Using the given information and the calculations above, the mass percentage of iron in the