Question

Определите количество гидроксида калия (моль), содержащееся в 3 л 25%-го раствора (плотность 1,24г/мл)

Answer 1

определи массу раствора mр-ра=3000*1,24=3720г а далее находи массу КОН

m(КОН)=3720*0,25=930г.

его количество n(KOH)=930/56=16.6моль

Answer 2

Calculation of the Amount of Potassium Hydroxide (in moles) in a 3 L 25% Solution

To determine the amount of potassium hydroxide (KOH) in moles present in a 3 L 25% solution with a density of 1.24 g/mL, we need to follow a step-by-step calculation.

1. Calculate the mass of the solution: - The density of the solution is given as 1.24 g/mL. - The volume of the solution is 3 L. - Using the formula: mass = volume × density, we can calculate the mass of the solution. - mass = 3 L × 1.24 g/mL = 3.72 kg.

2. Calculate the mass of KOH in the solution: - The solution is 25% KOH, which means that 25% of the mass of the solution is KOH. - Using the formula: mass of KOH = mass of solution × percentage of KOH. - mass of KOH = 3.72 kg × 0.25 = 0.93 kg.

3. Convert the mass of KOH to moles: - To convert the mass of KOH to moles, we need to know the molar mass of KOH. - The molar mass of KOH is calculated by adding the atomic masses of potassium (K), oxygen (O), and hydrogen (H). - The atomic masses are: K = 39.10 g/mol, O = 16.00 g/mol, H = 1.01 g/mol. - Molar mass of KOH = 39.10 g/mol + 16.00 g/mol + 1.01 g/mol = 56.11 g/mol.

- Now, we can calculate the number of moles of KOH: - moles of KOH = mass of KOH / molar mass of KOH. - moles of KOH = 0.93 kg / 56.11 g/mol = 16.57 mol.

Therefore, the 3 L 25% solution contains approximately 16.57 moles of potassium hydroxide (KOH).

Please note that the calculation assumes that the density of the solution remains constant throughout the volume.