Using mass percentages:-

The American Dental Association recommends that you should consume 3.0 mg of fluoride a day. If you get your fluoride in the form of sodium fluoride, what mass of sodium fluoride should you ingest?

I'm across the Bay, so I'm sure any answer would not apply in OAKLAND. Please use your SUBJECT matter in the SUBJECT box so a chemistry tutor will see it. He might not be in Oakland, though.

To determine the mass of sodium fluoride you should ingest to obtain 3.0 mg of fluoride, we need to use the concept of mass percentages. First, we need to know the mass percentage of fluoride in sodium fluoride.

Sodium fluoride is a compound composed of sodium (Na) and fluoride (F). Its chemical formula is NaF. To calculate the mass percentage of fluoride in sodium fluoride, we need to compare the molar mass of fluoride to the molar mass of sodium fluoride.

The molar mass of fluoride (F) is approximately 19.0 g/mol, while the molar mass of sodium fluoride (NaF) is approximately 41.0 g/mol (22.99 g/mol for sodium and 19.0 g/mol for fluoride).

To calculate the mass percentage of fluoride in sodium fluoride, divide the molar mass of fluoride by the molar mass of sodium fluoride and multiply by 100:

Mass percentage of fluoride in NaF = (molar mass of fluoride / molar mass of sodium fluoride) * 100

Mass percentage of fluoride in NaF = (19.0 g/mol / 41.0 g/mol) * 100
Mass percentage of fluoride in NaF ≈ 46.34%

Now that we know that the mass percentage of fluoride in sodium fluoride is approximately 46.34%, we can determine how much sodium fluoride you should ingest to obtain 3.0 mg of fluoride.

Let x be the mass of sodium fluoride in milligrams (mg). We can set up the following equation using mass percentages:

Mass of fluoride in sodium fluoride = Mass percentage of fluoride in sodium fluoride * Mass of sodium fluoride

3.0 mg = 46.34% * x mg

To solve for x, we can rearrange the equation:

x = (3.0 mg) / (46.34%)
x ≈ 6.47 mg

Therefore, you should ingest approximately 6.47 mg of sodium fluoride to obtain 3.0 mg of fluoride.