Calculating Mass Percent in Solutions

Mr. Millings explains how to calculate the mass percent of a solution, which involves dividing the mass of the solute by the mass of the entire solution and multiplying by 100%. He provides examples using saltwater, lactose in milk, and sodium nitrate solutions, demonstrating how to manipulate the mass percent formula to solve for different variables. The video emphasizes the importance of significant figures in calculations.

What is the formula for calculating mass percent in a solution?

• Mass of solution divided by mass of solute times 100

• Mass of solvent divided by mass of solute times 100

• Mass of solute divided by mass of solution times 100

• Mass of solute divided by mass of solvent times 100

Which of the following is NOT a component of a solution?

• Solute

• Solvent

• Solution

• Mass percent

In the saltwater example, what is the mass of the entire solution if 15g of salt is added to 100g of water?

• 115g

• 150g

• 200g

• 100g

What is the density of water used in the saltwater example?

• 2 g/mL

• 0.5 g/mL

• 1 g/mL

• 1.5 g/mL

How can the mass percent formula be rearranged to solve for the mass of the solute?

• Mass of solution times mass percent divided by 100

• Mass of solution divided by mass percent times 100

• Mass of solute times 100 divided by mass percent

• Mass percent times 100 divided by mass of solution

If a solution is made by mixing 25.5g of salt with 150g of water, what is the mass percent of salt?

• 17.5%

• 14.5%

• 15.5%

• 16.5%

What is the mass of lactose in 175g of milk if the milk contains 4.5% lactose by mass?

• 7.9g

• 10.9g

• 8.9g

• 9.9g

How do you calculate the mass of a solution if you know the mass of the solute and the mass percent?

• Mass percent times 100 divided by mass of solute

• Mass of solute times 100 divided by mass percent

• Mass of solute divided by mass percent times 100

• Mass percent divided by mass of solute times 100

In the example with sodium nitrate, what is the mass of the solution if 75g of sodium nitrate is dissolved to make a 15% solution?

• 500g

• 550g

• 450g

• 400g

What is the significance of significant figures in calculating mass percent?

• They only apply to the mass of the solute.

• They determine the precision of the measurement.

• They are not important in mass percent calculations.

• They only apply to the mass of the solution.