Question

Рассчитайте объем водорода, который выделится при взаимодействии 2,8 г железа с 20 г 25%-ной соляной кислоты.(ответ 1,12 л)

Answer 1

Тут все легко, если знать формулы)

Answer 2

Calculation of Hydrogen Gas Volume

To calculate the volume of hydrogen gas that will be released when 2.8 g of iron reacts with 20 g of 25% hydrochloric acid, we need to use the balanced chemical equation for the reaction between iron and hydrochloric acid:

Fe + 2HCl → FeCl2 + H2

From the equation, we can see that 1 mole of iron reacts with 2 moles of hydrochloric acid to produce 1 mole of hydrogen gas. We can use this information to calculate the moles of iron and hydrochloric acid in the given amounts.

1. Calculate the moles of iron: - The molar mass of iron (Fe) is 55.85 g/mol. - We have 2.8 g of iron. - Using the formula: moles = mass / molar mass, we can calculate the moles of iron: - Moles of iron = 2.8 g / 55.85 g/mol = 0.0501 mol

2. Calculate the moles of hydrochloric acid: - The molar mass of hydrochloric acid (HCl) is 36.46 g/mol. - We have 20 g of 25% hydrochloric acid. - To calculate the mass of hydrochloric acid in the solution, we multiply the total mass by the percentage of hydrochloric acid: - Mass of hydrochloric acid = 20 g * 0.25 = 5 g - Using the formula: moles = mass / molar mass, we can calculate the moles of hydrochloric acid: - Moles of hydrochloric acid = 5 g / 36.46 g/mol = 0.137 mol

3. Determine the limiting reactant: - To determine the limiting reactant, we compare the moles of iron and hydrochloric acid. - The ratio of iron to hydrochloric acid in the balanced equation is 1:2. - Since the ratio is 1:2, we need twice as many moles of hydrochloric acid as moles of iron for complete reaction. - The moles of hydrochloric acid (0.137 mol) are greater than twice the moles of iron (2 * 0.0501 mol = 0.1002 mol). - Therefore, iron is the limiting reactant.

4. Calculate the moles of hydrogen gas produced: - From the balanced equation, we know that 1 mole of iron produces 1 mole of hydrogen gas. - Therefore, the moles of hydrogen gas produced will be equal to the moles of iron: - Moles of hydrogen gas = 0.0501 mol

5. Convert moles of hydrogen gas to volume: - At standard temperature and pressure (STP), 1 mole of any gas occupies 22.4 liters. - Therefore, the volume of hydrogen gas produced will be: - Volume of hydrogen gas = 0.0501 mol * 22.4 L/mol = 1.12 L

Therefore, the volume of hydrogen gas that will be released when 2.8 g of iron reacts with 20 g of 25% hydrochloric acid is 1.12 liters.