Question

Many popular brands of toothpaste contain about 1.00 mg of fluoride per gram of toothpaste. The fluoride compound that is most often used in toothpaste is sodium fluoride, NaF, which is 45% fluoride by mass. How many milligrams of NaF are in a 250.0 g tube of toothpaste

Answer 1

Answer:

Mass of NaF in 250 g tube of toothpaste = 100 mg of NaF

Explanation:

Mass of fluoride per gram of toothpaste = 1 mg

From the given data, the fluoride compound that is most often used in toothpaste is sodium fluoride, NaF, which is 45% fluoride by mass, mass of sodium fluoride per gram of toothpaste can be determined as follows:

1 mg of fluoride per gram of toothpaste = 45% total mass of NaF per gram of toothpaste

100% mass of NaF in toothpaste = 100/45 * 1 mg = 2.22 mg of NaF.

Therefore, mass of NaF per gram of toothpaste is 2.22 mg.

The mass of NaF in 250 g of toothpaste is then calculated below:

In 250 g of toothpaste, mass of NaF = 250 * 2.22 mg = 99.9 mg of NaF