Determine the number of moles of the compound and determine...

Determine the number of moles of the compound and determine the number of moles of each type of atom in each of the following: (a) 2.12 g of potassium bromide, KBr (b) 0.1488 g of phosphoric acid, $\mathrm{H}_{3} \mathrm{PO}_{4}$ (c) 23 kg of calcium carbonate, $\mathrm{CaCO}_{3}$ (d) 78.452 g of aluminum sulfate, $A_{2}\left(S O_{4}\right)_{3}$ (e) 0.1250 mg of caffeine, $C_{8} H_{10} N_{4} O_{2}$

Determine the number of moles of the compound and determine the number of moles of each type of atom in each of the following:
(a) 2.12 g of potassium bromide, KBr
(b) 0.1488 g of phosphoric acid, $\mathrm{H}_{3} \mathrm{PO}_{4}$
(c) 23 kg of calcium carbonate, $\mathrm{CaCO}_{3}$
(d) 78.452 g of aluminum sulfate, $A_{2}\left(S O_{4}\right)_{3}$
(e) 0.1250 mg of caffeine, $C_{8} H_{10} N_{4} O_{2}$

Key Concepts

Chemical Formula and Atomic Composition

A chemical formula indicates the types and numbers of atoms present in a compound. Understanding a compound’s formula allows one to determine the stoichiometric ratios of elements, which is essential for calculating the moles of individual atoms present in a given sample.

Mass-to-Mole Conversion

Mass-to-mole conversion is the process of determining the number of moles from a given mass using the formula: moles = mass / molar mass. This conversion is fundamental in stoichiometry, enabling the quantification of substances in chemical reactions.

Mole Concept

The mole is a fundamental unit in chemistry that represents 6.022 x 10^23 particles (Avogadro's number) of a substance. It provides a bridge between the atomic scale and the macroscopic scale measurements, allowing chemists to count atoms and molecules by weighing them.

Molar Mass

Molar mass is the mass of one mole of a substance, usually expressed in grams per mole (g/mol). It is calculated by summing the standard atomic weights of all the atoms in a molecule, thus converting a molecular formula into a measurable mass.

Transcript

00:01 Hi everyone so in this question they ask that by the number of holes of the compound and it by number of moles of each type of atoms in the following so is 2 .12 gram of potassium bromide so a part n is equal to 2 .12 divided by 119 and that is equal to 0 .0 .0 178 moles of kbr.

00:44 So number of moles of k plus and br minus that is equal to 0 .078 into 6 .022 into 10 dash to 23 and that is equal to 0 .078 into 6 .022 into 10 dash to 23 and that is equal to 0 .0.

01:16 1072 into 10 dash to 23.

01:20 So that is equal to 1 .072 into 10 dash to 22 moles and therefore number of moles of k plus and we are minus that is equal to 1 .072 into 10 dash to 22 moles into 10 dash to 22 moles then b part 0 .148 gram of phosphoric acid, 0 .148 gram of h3po4.

02:42 So n is equal to 0 .148 divided by 98 and that is equal to 0 .01 52, 0 .00.

03:03 0 .00152 malls.

03:13 Then number of moles of 3 hydrogen atom number of moles of 3 hydrogen atom that is equal to 3 into 0 .502 into 6 .022 into 10 -2323 that is equal to 2 .75 into 10 -121 hydrogen atoms.

04:01 Then number of moles of phosphorus, number of moles of phosphorus that is equal to 1 into 0 .00152 into 6 .022 into 10 -2.

04:25 23 that is equal to 9 .15 into 10 -20 atoms or 20 moles, 20 atoms.

04:48 Then next number of moles of auction atom, number of malls of auction atom, malls of auction atoms that is equal to 4 into 0.

05:11 0 .052 into 6 .022 into 10 .2 into 10 .23 and that is equal to 3 .66 into 10 dash to 21 atoms.

05:42 Then c part 23 kilogram that is equal to 23 ,000 grams.

06:01 So, yon is equal to 23 ,000 grams.

06:02 So, yon is equal to 20.

06:05 23 ,000 divided by 100 and that is equal to 230 modes.

06:18 So, you know, number of calcium atoms, number of calcium, number of most of calcium atoms, number of moles of calcium atoms, that is equal to 230 into, into 6 .022 into 10 -23 that is equal to 1 .38 into 10 -26 terms.

07:09 Then number of moles of carbon atom, of carbon atom that is equal to 230 into 6 .022 into 10 -232 into 10 -2 -23 and that is equal to 1 .38 into 10 -2 26 atoms...

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