Calculate the mass of sodium sulphate that isquired to prepare 20% (massby mass%) solution in 100g of water.

To calculate the mass of sodium sulphate required to prepare a 20% (mass by mass%) solution in 100g of water, we need to follow these steps:

Step 1: Determine the total mass of the solution. The total mass of the solution is the sum of the mass of water and the mass of sodium sulphate. In this case, it is 100g (mass of water) + mass of sodium sulphate.

Step 2: Calculate the mass of sodium sulphate. To find the mass of sodium sulphate, we need to use the mass percentage formula: Mass percentage = (mass of solute / mass of solution) x 100

In this case, the mass percentage is 20% and the mass of the solution is 100g. Let's assume the mass of sodium sulphate is x grams.

20% = (x / (100g + x)) x 100

Step 3: Solve the equation. To solve the equation, we can cross-multiply and simplify:

20(100g + x) = x

2000g + 20x = x

2000g = x - 20x

2000g = -19x

x = -2000g / 19

Step 4: Calculate the mass of sodium sulphate. Now, we can substitute the value of x into the equation to find the mass of sodium sulphate:

Mass of sodium sulphate = -2000g / 19

Please note that the negative sign indicates that the mass of sodium sulphate is negative, which is not physically possible. Therefore, there might be an error in the calculation or the given information.