Question

Задача химия, срочно! В 753 г воды растворили 47 г NiCl2•5H2O, вычислите массовую долю безводной соли.

Answer 1

Ответ:

3,5%

Объяснение:

В 59 + 35,5*2 + 5*(1*2 + 16) = 220 граммах кристаллогидрата содержится 59 + 35,5*2 = 130 граммов безводной соли. Тогда в 47 граммах кристаллогидрата будет содержаться 47*130/220 = 27,8 грамма хлорида никеля. Потому массовая доля безводной соли в полученном растворе равна 27,8:(753 + 47) = 0,035, или 3,5%.

Answer 2

Calculating the Mass Fraction of Anhydrous Salt

To calculate the mass fraction of anhydrous salt in the given solution, we can use the following formula:

Mass fraction of anhydrous salt = (Mass of anhydrous salt / Total mass of solution) × 100%

First, we need to find the mass of the anhydrous salt and the total mass of the solution.

Finding the Mass of Anhydrous Salt

The molar mass of NiCl2•6H2O (nickel(II) chloride hexahydrate) is 237.69 g/mol, and the molar mass of NiCl2 (anhydrous nickel(II) chloride) is 129.6 g/mol. Using this information, we can calculate the mass of the anhydrous salt.

Mass of NiCl2•5H2O = 47 g

Molar mass of NiCl2•6H2O = 237.69 g/mol Molar mass of NiCl2 = 129.6 g/mol

The mass of the anhydrous salt can be calculated using the following steps:

1. Calculate the moles of NiCl2•6H2O. 2. Calculate the moles of NiCl2. 3. Use the moles of NiCl2 to find the mass of NiCl2.

Let's proceed with these calculations.

Calculating Moles and Mass of Anhydrous Salt

1. Moles of NiCl2•6H2O: - Moles = Mass / Molar mass - Moles = 47 g / 237.69 g/mol - Moles ≈ 0.1977 mol

2. Moles of NiCl2: - Since NiCl2•6H2O has 2 moles of chloride ions, the moles of NiCl2 will be twice the moles of NiCl2•6H2O. - Moles of NiCl2 = 2 * Moles of NiCl2•6H2O - Moles of NiCl2 ≈ 2 * 0.1977 mol - Moles of NiCl2 ≈ 0.3954 mol

3. Mass of NiCl2: - Mass = Moles * Molar mass - Mass = 0.3954 mol * 129.6 g/mol - Mass ≈ 51.24 g

Now that we have the mass of the anhydrous salt, we can proceed to calculate the total mass of the solution.

Calculating the Total Mass of the Solution

The total mass of the solution is the sum of the mass of water and the mass of NiCl2•5H2O.

Mass of water = Total mass of solution - Mass of NiCl2•5H2O Mass of water = 753 g - 47 g Mass of water = 706 g

Now, we can calculate the mass fraction of the anhydrous salt.

Calculating the Mass Fraction of Anhydrous Salt

Mass fraction of anhydrous salt = (Mass of anhydrous salt / Total mass of solution) × 100% Mass fraction of anhydrous salt = (51.24 g / 753 g) × 100% Mass fraction of anhydrous salt ≈ 6.80%

So, the mass fraction of the anhydrous salt in the solution is approximately 6.80%.