Concentration Units and Calculations

Professor Chulai concludes the discussion on concentration units by introducing parts per million (ppm) and parts per billion (ppb). These units are used to express very small concentrations, often for toxins. The video includes example calculations to demonstrate how to convert and calculate using ppm and ppb, emphasizing their importance in describing tiny concentrations. The video wraps up with a summary of different concentration units and a preview of the next chapter.

What are the two concentration units discussed in this video?

• Grams per liter and Milligrams per liter

• Percent weight by weight and Percent volume by volume

• Parts per million and Parts per billion

• Molarity and Molality

Why are ppm and ppb preferred for expressing very small concentrations?

• They are easier to calculate.

• They provide a more accurate representation of small concentrations.

• They are the standard units in all chemical calculations.

• They are used for large concentrations.

How is parts per million (ppm) mathematically expressed?

• Volume of solute divided by volume of solution times 10^9

• Volume of solute divided by volume of solution times 10^6

• Mass of solute divided by mass of solution times 10^9

• Mass of solute divided by mass of solution times 10^6

How is parts per billion (ppb) mathematically expressed?

• Volume of solute divided by volume of solution times 10^9

• Volume of solute divided by volume of solution times 10^6

• Mass of solute divided by mass of solution times 10^6

• Mass of solute divided by mass of solution times 10^9

In the example of lead in water, what is the first step in the calculation?

• Convert the volume of water to mass using the density of water.

• Directly calculate the mass of lead using ppm.

• Convert the mass of lead to micrograms.

• Use the molarity of the solution.

What is the final mass of lead in micrograms in the example problem?

• 4.5 grams

• 4.5 micrograms

• 5 micrograms

• 5 grams

In the mercury example, what is the mass of the solution?

• 50.0 milligrams

• 0.48 milligrams

• 50.0 grams

• 0.48 grams

What is the concentration of mercury in parts per million in the example problem?

• 9.6 ppm

• 960 ppm

• 0.96 ppm

• 96 ppm

What is the concentration of mercury in parts per billion in the example problem?

• 960 ppb

• 9600 ppb

• 9.6 ppb

• 96 ppb

What is the relationship between ppm and ppb?

• ppb is 1000 times larger than ppm

• ppm is 100 times larger than ppb

• ppm is 1000 times larger than ppb

• ppb is 100 times larger than ppm