Question

Навеску алюминия массой 2,7 г сожгли в закрытом сосуде, содержащем 4.2 л хлора Сосуд охладили до комнатной температуры, полученное твердое вещество растворили в 300 мл 30% раствора гидроксида натрия (плотность 1,28 г/мл). Какова массовая доля воды в полученном растворе? Приведите уравнение упомянутых в условии реакций.

Answer 1

m(Cl)=V:Vm×M=6,5625г

m(ppa)=300×1,28=384г

m(ppa)=6,5625+384=390,5625г

m(NaOH)=300×0,3=90г

m(H2O)=384-90=294г

w(H2O)=294:390,5625≈0,7528×100%=75,28%

Answer 2

Calculation of the Mass Fraction of Water in the Solution

To determine the mass fraction of water in the solution, we need to calculate the mass of water and the total mass of the solution.

Given: - Mass of aluminum = 2.7 g - Volume of chlorine = 4.2 L - Volume of sodium hydroxide solution = 300 mL - Concentration of sodium hydroxide solution = 30% (w/v) - Density of sodium hydroxide solution = 1.28 g/mL

First, let's calculate the mass of water in the sodium hydroxide solution:

Step 1: Calculate the mass of sodium hydroxide in the solution. To do this, we need to find the mass of the sodium hydroxide solution by multiplying its volume by its density:

Mass of sodium hydroxide solution = Volume of sodium hydroxide solution * Density of sodium hydroxide solution Mass of sodium hydroxide solution = 300 mL * 1.28 g/mL

Step 2: Calculate the mass of sodium hydroxide in the solution. To do this, we multiply the mass of the sodium hydroxide solution by its concentration:

Mass of sodium hydroxide = Mass of sodium hydroxide solution * Concentration of sodium hydroxide Mass of sodium hydroxide = (300 mL * 1.28 g/mL) * 0.30

Step 3: Calculate the mass of water in the solution. To do this, we subtract the mass of sodium hydroxide from the mass of the solution:

Mass of water = Mass of sodium hydroxide solution - Mass of sodium hydroxide

Now, let's calculate the total mass of the solution:

Step 4: Calculate the total mass of the solution. To do this, we add the mass of aluminum, the mass of chlorine, and the mass of water:

Total mass of the solution = Mass of aluminum + Mass of chlorine + Mass of water

Finally, we can calculate the mass fraction of water in the solution:

Step 5: Calculate the mass fraction of water. To do this, we divide the mass of water by the total mass of the solution and multiply by 100 to express it as a percentage:

Mass fraction of water = (Mass of water / Total mass of the solution) * 100

Equations for the Mentioned Reactions

Unfortunately, the provided search snippets do not contain the equations for the mentioned reactions. However, I can provide you with the general equations for the reactions involved:

1. The combustion of aluminum: 2 Al + 3 Cl2 → 2 AlCl3

2. The dissolution of the solid substance in sodium hydroxide solution: AlCl3 + 3 NaOH → Al(OH)3 + 3 NaCl

Please note that these equations are general representations of the reactions and may not specifically correspond to the conditions mentioned in the question.

I hope this helps! Let me know if you have any further questions.