Question

8. Какая масса соли необходима для приготовления 110 г раствора с массовой долей хлорида натрия 20% ? 1) 11 г 2) 15 г 3) 22 г 4) 55 г 9. Азотная кислота взаимодействует с 1) хлоридом натрия 2) гидроксидом калия 3) оксидом кремния 4) бензолом 5) сульфатаом бария 6) карбонатом кальция Ответ: __________________ . 11. Запишите сокращенные ионные уравнения возможных реакций раствора гидроксида калия с веществами из списка: хлорид натрия, сульфат железа(II), азотная кислота, нитрат меди(II), оксид магния. 12. К раствору массой 60 г с массовой долей сахара 10% добавили 40 г воды. Вычислить массовую долю вещества в полученном растворе.

Answer 1

1)-22гответ3
2)ответ-2 ,4,6
11задание
2КОН+FeSO4=K2SO4+Fe(OH)2-осадок бурого цвета
Fe2+ +2OH-=Fe(OH)2
KOH+HNO3=KNO3+H2O
OH- +H-=H2O
12
W=mв-ва/Mр-ра
m=60*0,1(10/100)=6 г
W=(6/60+40)100%=6% это ответ

Answer 2

Question 8: To calculate the mass of salt needed to prepare a 110 g solution with a mass fraction of sodium chloride of 20%, we can use the formula:

Mass of salt = (Mass fraction of salt) * (Total mass of solution)

In this case, the mass fraction of sodium chloride is 20%, or 0.20. The total mass of the solution is given as 110 g. Plugging these values into the formula:

Mass of salt = 0.20 * 110 g = 22 g

Therefore, the mass of salt needed to prepare the solution is 22 g.

Question 9: Nitric acid reacts with various substances. To determine which substance it reacts with, we need to look at the chemical equation for the reaction. Without the chemical equation, it is not possible to determine the specific substance that nitric acid reacts with.

Question 11: To write the ionic equations for the reactions of potassium hydroxide solution with the substances listed, we need to know the chemical formulas of the substances. Here are the ionic equations for the reactions:

1) Potassium hydroxide reacts with sodium chloride:

2 KOH + NaCl → 2 KCl + H2O

2) Potassium hydroxide reacts with iron(II) sulfate:

2 KOH + FeSO4 → Fe(OH)2 + K2SO4

3) Potassium hydroxide reacts with nitric acid:

KOH + HNO3 → KNO3 + H2O

4) Potassium hydroxide does not react with benzene.

5) Potassium hydroxide reacts with barium sulfate:

KOH + BaSO4 → Ba(OH)2 + K2SO4

6) Potassium hydroxide reacts with calcium carbonate:

2 KOH + CaCO3 → Ca(OH)2 + K2CO3

Question 12: To calculate the mass fraction of the substance in the resulting solution, we need to know the initial mass of the solute (sugar) and the total mass of the resulting solution (sugar + water).

The initial mass of the solute is 60 g and the mass fraction of sugar in the solution is given as 10%, or 0.10. The mass of water added is 40 g.

To calculate the total mass of the resulting solution, we add the mass of sugar and the mass of water:

Total mass of solution = mass of sugar + mass of water = 60 g + 40 g = 100 g

To calculate the mass fraction of the substance in the resulting solution, we use the formula:

Mass fraction = (Mass of substance) / (Total mass of solution)

Plugging in the values:

Mass fraction of substance = (60 g) / (100 g) = 0.60

Therefore, the mass fraction of the substance in the resulting solution is 60%.