Determine the chemical formula of each compound and use it...

Determine the chemical formula of each compound and use it to calculate the mass percent composition of each constituent element.
a. perchloric acid
b. phosphorus pentachloride
c. nitrogen triiodide
d. carbon dioxide

Key Concepts

Chemical Nomenclature

This concept involves interpreting the names of compounds to determine their corresponding chemical formulas. It requires an understanding of ion charges, oxidation states, and the systematic nomenclature rules established by IUPAC. By correctly identifying the constituent ions and their respective ratios, one can derive the accurate formula for any ionic compound.

Molar Mass Calculation

Molar mass calculation is a fundamental concept that entails adding up the atomic masses of all atoms in a compound's formula to determine the mass of one mole of that compound. It is crucial for converting between mass and moles and is a necessary step in various quantitative chemistry calculations, including percentage composition.

Mass Percent Composition Calculation

This concept describes the process of determining the percentage by mass of each element in a compound. It is calculated by dividing the total mass of a particular element (from its contribution in the compound's formula) by the compound's molar mass, and then multiplying the result by 100. This calculation helps in understanding the relative contributions of each element to the overall structure of the compound.

Transcript

00:04 All right, guys, we are doing problem number 124 of chapter 3 in chemistry and molecular approach.

00:12 In terms of the chemical formula of each compound, then use it to calculate the mass percent composition of each element.

00:19 So a is perchloric.

00:21 So you may remember that chloric acid, that's hcl -03, per -chloric, that prefix per, that means you have one more oxygen.

00:30 So that's, it's h -c -l -o -4.

00:37 Now, let's look at each atom.

00:38 Atom cd mass composition so let's so percent hydrogen percent oxygen and percent chlorine so one hydrogen so a molecular weight of one divided by one plus 35 .5 for chlorine plus four times 16 for oxygen and i'll just add everything up all right so for the percent hydrogen that's going to be 0 .995%.

02:45 And for oxygen, 4 times 16, about 1 plus 35 .15 plus 4 times 16.

02:58 That's going to be 63 .68.

03:10 Percent and now for chlorine 35 .5 divided by one plus 35 .15 plus four times 16.

03:21 That's going to be 35 .5 .32%.

03:35 All right.

03:49 Next, so these are the mass percent composition of each element.

03:55 Next, we're going to go to phosphorus pentacloride.

04:01 Now remember this basic setup for naming molecular as covalent compounds you have your base elements and then the prefix that's going to determine how many you have so we're going to have phosphorus and pentaclorid that means we're going to have five chlorines if if there's a if there's nothing saying how many phosphorus we have we assume we just have one let's put percent chlorine and the molecular weight of the atomic weight of phosphorus that that's approximately 31 .5.

05:05 And let's set this one up.

05:26 All right.

05:27 So now let's figure out how much chlorine have...

Please give Ace some feedback