Calculate the molar mass of each of the following: (a) the...

Calculate the molar mass of each of the following: (a) the anesthetic halothane, $\mathrm{C}_{2} \mathrm{HBrClF}_{3}$ (b) the herbicide paraquat, $\mathrm{C}_{12} \mathrm{H}_{14} \mathrm{N}_{2} \mathrm{Cl}_{2}$ (c) caffeine, $\mathrm{C}_{8} \mathrm{H}_{10} \mathrm{N}_{4} \mathrm{O}_{2}$ (d) urea, $\mathrm{CO}\left(\mathrm{NH}_{2}\right)_{2}$ (e) a typical soap, $\mathrm{C}_{17} \mathrm{H}_{35} \mathrm{CO}_{2} \mathrm{Na}$

Calculate the molar mass of each of the following:
(a) the anesthetic halothane, $\mathrm{C}_{2} \mathrm{HBrClF}_{3}$
(b) the herbicide paraquat, $\mathrm{C}_{12} \mathrm{H}_{14} \mathrm{N}_{2} \mathrm{Cl}_{2}$
(c) caffeine, $\mathrm{C}_{8} \mathrm{H}_{10} \mathrm{N}_{4} \mathrm{O}_{2}$
(d) urea, $\mathrm{CO}\left(\mathrm{NH}_{2}\right)_{2}$
(e) a typical soap, $\mathrm{C}_{17} \mathrm{H}_{35} \mathrm{CO}_{2} \mathrm{Na}$

Key Concepts

Atomic Weights (Periodic Table)

Atomic weights represent the average mass of an element’s atoms, taking into account the distribution of isotopes, and are provided on the periodic table. These weights are essential for molar mass calculations as they provide the numerical values needed to multiply by the number of atoms in the compound.

Molar Mass Calculation

This concept involves computing the mass of one mole of a compound by summing the atomic masses of each element present in the chemical formula, multiplied by the number of times each element appears. It is fundamental in stoichiometry for converting between mass and moles, and for analyzing chemical reactions quantitatively.

Molecular Formula Interpretation

Understanding a molecular formula involves identifying the symbols of the elements and their corresponding subscripts, which indicate the number of atoms of each element in the molecule. This interpretation is crucial because it determines the contribution of each element to the overall molar mass of the compound.

Transcript

00:01 In this question, we've been asked to determine the molar mass of each of the following molecules.

00:07 And in order to determine the molar mass, we'll have to know the mulamass of the individual elements that make up this molecule and sum that up.

00:21 Right.

00:22 So for the first one, we have c2h, dr, cl, f3.

00:27 So we have two carbons, one hydrogen, one bromine, one chlorine, and three fluorines.

00:31 Right so the molar mass is just going to be the summation of the masses yeah the molecular masses of these elements so for part a in order to calculate the molar mass we have to first get the molar mass of a single carbon atom which is 12 .011 because we have two carbons multiplied that by two and when i'm going to ignore the units and just include that in my final answer because that's what's more relevant.

01:15 So we have 12 .01 times 2 plus hydrogen we have 1 .008 and bromine is 79 .904.

01:32 Chlorine on the other hand is 35 .45 and fluorine keep in mind that we have three fluorines.

01:42 Mullah muscle 1 fluorine is 18 .998, multiply by 3 because we have 3 florens in our molecule.

01:52 Right, so summing this up, we end up getting 197 .378.

01:59 The units for the molarasa grams per mole.

02:04 Moving on, in part b, we have c12, h14, and 2, cl2.

02:10 Just as we did in part a, we're going to do a similar for part b just find out you know some of the molar masses of the respective elements that make of this compound so we have c12 so carbon we said has a more muscle 12 .01 grams per mole now the 12 carbons we multiply that by 12 and there are 14 hydrogens so it's 1 .008 by 14 of 14 of 2nd which is 14 .007 times 2 and we have two chlorine.

02:56 It has the amount of 35 .45 grams per mole, but we have two of those multiply by 2.

03:03 So our final result is going to be 257 .158 grams per mole...

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