Question

сколько грамм воды Na(OH) необходимо взять для приготовления 4% раствора? срочняк нужно,ребята помогите

Answer 1

Mr(NaOH)=40г/моль, значит 
1 молярный раствор содержит 40 г NaОН в 1 л, => 0,1 М раствор - 4 г/л
m=Cм*Mr*V/1000=0,1*40*125/1000=0,5 г

Answer 2

Calculating the Amount of Water Needed for a 4% Solution of NaOH

To calculate the amount of water needed to prepare a 4% solution of NaOH, we can use the formula for calculating the concentration of a solution:

Concentration = (Mass of solute / Volume of solution) * 100

In this case, we want to find the volume of water needed to dissolve a certain amount of NaOH to make a 4% solution. The mass of NaOH needed can be calculated using the formula:

Mass of solute = (Concentration * Volume of solution) / 100

Let's calculate the amount of water needed using this information.

Given: - Concentration of NaOH solution = 4% - Volume of solution = 1000 grams (1 liter)

Using the formula, we can calculate the mass of NaOH needed: Mass of NaOH = (4 * 1000) / 100 = 40 grams

So, to prepare a 4% solution of NaOH, you would need to dissolve 40 grams of NaOH in 1000 grams (1 liter) of water.