A tube of toothpaste contains 0.76 g of sodium...

Key Concepts

Avogadro's Number

Avogadro's number, 6.022 x 10^23 particles per mole, is a key constant used to convert between the number of moles of a substance and the number of atoms or molecules. This is critical when determining the total number of fluorine atoms present.

Mole Concept

The mole concept connects the mass of a substance with the number of its constituent particles using the molar mass. This concept facilitates converting the given mass of the compound into a corresponding number of moles.

Unit Conversion

Unit conversion is essential for ensuring that units are consistent throughout a calculation. For example, converting grams to milligrams or other units is necessary to interpret the final results in the desired format.

Stoichiometry

Stoichiometry is the quantitative relationship between reactants and products in a chemical reaction or compound. In this context, it is used to determine the proportion of fluorine within sodium monofluorophosphate based on its chemical formula.

Molar Mass Calculation

Molar mass calculation involves summing the atomic masses of all atoms in a molecule, which is fundamental for converting mass measurements to moles. In this problem, the atomic masses of sodium, phosphorus, oxygen, and fluorine are used to compute the compound's molar mass.

Transcript

00:02 Hi there.

00:03 In this problem, we have 0 .76 grams of sodium monofllorofosophosphate.

00:16 So the formula for that is given.

00:19 It is na2 -p -o -3f.

00:26 And we have two problems here.

00:28 We want to first determine the mass of fluorine in milligrams that is present.

00:34 And then we want to know how many fluorine atoms are present.

00:39 So to solve this, we are going to have to first calculate percent composition for the flooring.

00:56 So in other words, in this compound, what percent of the mass of this compound is due to the flooring? so we want to first calculate that, not really a question mark, but a statement.

01:13 The next thing we want to do then is once we have that percent composition, we can multiply by that mass to determine how many of those grams.

01:22 Or the flooring.

01:25 So we're going to use that to calculate mass of flooring.

01:37 And we can convert that to milligrams as the question asks.

01:41 And then finally, we can use the mass of fluorine to convert that to moles of fluorine.

01:53 And finally, use avogadro's number to get us to atoms of fluorine.

02:00 All right.

02:01 So those are the steps that we are going to follow.

02:04 So the first thing, for letter a, we were trying to figure out the mass of the flooring in milligrams.

02:14 So as i mentioned, the first thing we need to do is calculate percent composition.

02:20 So the percent composition for the flooring, that is going to be equal to the mass of flooring.

02:33 I'm talking in terms of molar masses now.

02:37 The mass of the flooring divided by the mass of the compound and multiplying that by 100 to change it into a percent.

02:51 So looking at the periodic table, the mass of the flooring is 19 .00 grams per mole, and the molar mass of the compound, i will arrive at that by adding the mass of two sodiums to the mass of one phosphorus plus three oxygens and one fluorine.

03:12 And i get 143 .95 grams per mole for the compound.

03:21 Calculating this and multiplying by 100 to change it to a percent, i find that this compound is 13 .2 percent flooring by mass.

03:35 Now that i know that, i can take the mass that was given...

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