Question

Внаслідок розчинення 10 г технічного цинку у надлишку хлоридної кислоти виділилось 3,36 л водню. Визначте масову частку (%) домішок у зразку цинку.

Answer 1

Ответ:

2,5%

Объяснение:

в фото

Answer 2

Calculation of the Mass Fraction of Impurities in the Zinc Sample

To determine the mass fraction of impurities in the zinc sample, we need to calculate the mass of the impurities and the mass of the zinc.

Given: - Mass of technical zinc = 10 g - Volume of hydrogen gas evolved = 3.36 L

To calculate the mass of the impurities, we need to know the molar ratio between zinc and hydrogen gas. This can be determined using the balanced chemical equation for the reaction between zinc and hydrochloric acid:

Zn + 2HCl -> ZnCl2 + H2

From the equation, we can see that 1 mole of zinc reacts with 2 moles of hydrochloric acid to produce 1 mole of hydrogen gas. Therefore, the molar ratio between zinc and hydrogen gas is 1:1.

To calculate the moles of hydrogen gas evolved, we can use the ideal gas law:

PV = nRT

Where: - P is the pressure of the gas (assume standard pressure, 1 atm) - V is the volume of the gas (3.36 L) - n is the number of moles of the gas (to be calculated) - R is the ideal gas constant (0.0821 L·atm/mol·K) - T is the temperature of the gas (assume room temperature, around 298 K)

Rearranging the equation to solve for n, we have:

n = PV / RT

Substituting the values, we get:

n = (1 atm) * (3.36 L) / (0.0821 L·atm/mol·K * 298 K)

Now, we can calculate the moles of zinc reacted, which is equal to the moles of hydrogen gas evolved:

moles of zinc = moles of hydrogen gas = n

Next, we need to calculate the molar mass of zinc. The molar mass of zinc is 65.38 g/mol.

Finally, we can calculate the mass of the impurities:

mass of impurities = mass of zinc - mass of pure zinc

mass of impurities = 10 g - (moles of zinc * molar mass of zinc)

To find the mass fraction of impurities, we divide the mass of impurities by the mass of the zinc sample and multiply by 100:

mass fraction of impurities (%) = (mass of impurities / mass of zinc) * 100

Let's calculate the values:

1. Calculate the moles of hydrogen gas evolved: - P = 1 atm - V = 3.36 L - R = 0.0821 L·atm/mol·K - T = 298 K

n = (1 atm) * (3.36 L) / (0.0821 L·atm/mol·K * 298 K)

2. Calculate the mass of impurities: - moles of zinc = moles of hydrogen gas (from step 1) - molar mass of zinc = 65.38 g/mol - mass of impurities = 10 g - (moles of zinc * molar mass of zinc)

3. Calculate the mass fraction of impurities: - mass fraction of impurities (%) = (mass of impurities / mass of zinc) * 100

Please wait while I perform the calculations.