Determine the amount in grams of KCL that exists in 20.3 g. of a solution that contains 1.14% KCL by mass

Determine the amount in grams of KCL that exists in 20.3 g. of a solution that contains 1.14% KCL by mass

The Correct Answer and Explanation is:

To determine the amount of potassium chloride (KCl) in a solution, we use the definition of percent by mass. The percent by mass of a solute tells us how many grams of the solute are present in every 100 grams of the solution.

Given:

• Total mass of the solution = 20.3 grams
• Percent by mass of KCl = 1.14%

Step-by-step calculation:

Mass of KCl=1.14100×20.3\text{Mass of KCl} = \frac{1.14}{100} \times 20.3Mass of KCl=1001.14​×20.3Mass of KCl=0.0114×20.3=0.23142 grams\text{Mass of KCl} = 0.0114 \times 20.3 = 0.23142 \text{ grams}Mass of KCl=0.0114×20.3=0.23142 grams

Rounded to three significant figures:Mass of KCl≈0.231 grams\text{Mass of KCl} \approx \boxed{0.231 \text{ grams}}Mass of KCl≈0.231 grams​

Explanation

To solve this problem, we need to apply the concept of percentage by mass. This concept tells us how much of a substance, in this case potassium chloride (KCl), is present in a mixture or solution. A percent by mass value expresses the ratio of the mass of the solute to the total mass of the solution. This ratio is then multiplied by 100 to convert it into a percentage.

In our problem, we are told that the solution has a mass of 20.3 grams and contains 1.14 percent KCl by mass. This means that for every 100 grams of solution, 1.14 grams is KCl. To find out how many grams of KCl are in only 20.3 grams of solution, we set up a proportion.

This proportion involves converting the percentage into a decimal and multiplying it by the total solution mass. We convert 1.14 percent to a decimal by dividing it by 100, which gives 0.0114. We then multiply this decimal by 20.3 grams, the total mass of the solution. The result is 0.23142 grams, which we round to 0.231 grams for clarity and precision.

Therefore, in a 20.3-gram solution that is 1.14 percent KCl by mass, there are approximately 0.231 grams of KCl. This method can be applied to any similar problem involving percent composition by mass.