Chemistry: Molarity and Density of Solutions

These flashcards cover key concepts related to the calculation of molarity and density of solutions discussed in the chemistry lecture about hydrogen peroxide.

What is the molar mass used for calculating moles of C2H5OH when given a mass of 39.45 grams?

Moles of C2H5OH = 39.45 grams divided by the molar mass of C2H5OH.

What does a 3% hydrogen peroxide solution signify?

3% of the total mass is pure H2O2, while the rest is water.

How can you simplify calculations for molarity in problems where the volume is not given?

Assume a volume of one liter to make calculations easier.

What is the formula for density?

Density = mass/volume.

How do you find the mass of H2O2 in a 3% solution with a total mass of 1110 grams?

Mass of H2O2 = 3% of 1110 grams, which equals 33.3 grams.

What is the relationship between volume, density, and mass in solution calculations?

Mass must always be calculated from the volume using the density, mass = volume × density.

In the lecture, what volume was chosen for the hydrogen peroxide to make calculations simple?

One liter.

If 1 liter of H2O2 solution is used, what is the importance of knowing the density?

The density allows the calculation of the mass of the solution which is needed to find the molarity.

What happens when you change the assumed volume in a molarity problem?

Changing the volume will affect the mass and subsequently the molarity calculation.

What is the calculated molarity for the example given in the lecture?

0.979 N (normality of the solution).

How do you convert moles to mass in the context of the solution provided in the lecture?

Multiply the number of moles by the molar mass.