Question

К 540г 25%-ного раствора соды Na2CO3 добавили 20г соды и 140г воды. определите массовую долю соды в полученном растворе.

Answer 1

M(ве-ва)=540*0,25=135гр
w=mве-ва)/m(ра-ра)*100=135+20/540+20+140*100=22%

Answer 2

Calculation of the Mass Fraction of Sodium Carbonate (Na2CO3) in the Solution

To determine the mass fraction of sodium carbonate (Na2CO3) in the solution, we need to calculate the total mass of Na2CO3 in the solution and divide it by the total mass of the solution.

Given information: - Initial solution: 540g of 25%-concentration sodium carbonate (Na2CO3) solution. - Additional components added: 20g of sodium carbonate (Na2CO3) and 140g of water.

Let's calculate the total mass of Na2CO3 in the solution:

1. Calculate the mass of Na2CO3 in the initial solution: - Initial solution mass: 540g - Concentration of the initial solution: 25% - Mass of Na2CO3 in the initial solution: 540g * (25/100) = 135g

2. Calculate the mass of Na2CO3 added: - Mass of additional Na2CO3 added: 20g

3. Calculate the total mass of Na2CO3 in the solution: - Total mass of Na2CO3: 135g + 20g = 155g

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

1. Calculate the mass of water added: - Mass of water added: 140g

2. Calculate the total mass of the solution: - Total mass of the solution: 540g + 140g = 680g

Finally, let's calculate the mass fraction of Na2CO3 in the solution:

1. Calculate the mass fraction of Na2CO3: - Mass fraction of Na2CO3 = (Total mass of Na2CO3 / Total mass of the solution) * 100 - Mass fraction of Na2CO3 = (155g / 680g) * 100 = 22.79%

Therefore, the mass fraction of sodium carbonate (Na2CO3) in the obtained solution is approximately 22.79%.