A solution is prepared by 40 g of A and 36 g of water. Find the mass percentage of solute.

Understand the Problem

The question is asking to calculate the mass percentage of a solute (A) in a solution prepared with a specific mass of solute and solvent (water). The mass percentage can be found using the formula: (mass of solute / total mass of solution) * 100.

Answer

The mass percentage of solute (A) in the solution is $10\%$.

Steps to Solve

Identify the mass of solute and solvent

Let's determine the mass of solute (A) and the mass of the solvent (water). For example, if we have a mass of solute (A) equal to 5 grams and the mass of solvent (water) equal to 45 grams.

Calculate the total mass of the solution

To find the total mass of the solution, we add the mass of the solute to the mass of the solvent:

$$ \text{Total mass of solution} = \text{mass of solute} + \text{mass of solvent} $$

So, substituting our values:

$$ \text{Total mass of solution} = 5 , \text{g} + 45 , \text{g} = 50 , \text{g} $$

Calculate the mass percentage of the solute

Now we can use the mass percentage formula:

$$ \text{Mass percentage} = \left( \frac{\text{mass of solute}}{\text{total mass of solution}} \right) \times 100 $$

Substituting the known values into the formula gives us:

$$ \text{Mass percentage} = \left( \frac{5 , \text{g}}{50 , \text{g}} \right) \times 100 $$

Perform the final calculation

Now we need to calculate the mass percentage:

$$ \text{Mass percentage} = \left( 0.1 \right) \times 100 = 10% $$

The mass percentage of solute (A) in the solution is $10%$.

More Information

The mass percentage indicates the concentration of the solute in the solution, which can be important in various fields such as chemistry and biology. Understanding mass percentage is crucial for preparing solutions with desired concentrations.

Tips

Forgetting to convert grams to another unit if required by the problem.
Incorrectly calculating the total mass of the solution; be sure to add the mass of the solute and solvent accurately.
Not multiplying by 100 when finding the percentage.

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