How many moles of atoms are there in each of the following? a. 40.1 g Ca b. 11.5 g Na c. 5.87 g

step 1 In this video we will study about conversions. So conversions will be from grams to moles and at

How many moles of atoms are there in each of the following?...

Key Concepts

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated from the atomic masses of the elements that constitute the substance and plays a crucial role in converting between the mass of a substance and the number of moles present. This conversion is fundamental in many chemical calculations, including determining how many atoms or molecules are in a given sample by using its mass.

Avogadro's Number

Avogadro's number, 6.022 x 10^23, is the number of atoms, molecules, or other elementary entities in one mole of a substance. This constant is a cornerstone of the mole concept, as it provides the critical link between the number of particles and the measurable mass of a substance, enabling conversions from counts of atoms or molecules to moles and vice versa.

Mole Concept

The mole concept is a fundamental principle in chemistry that provides a bridge between the atomic scale and the macroscopic scale observed in the laboratory. It establishes that one mole of any substance contains the same number of entities (atoms, molecules, ions, etc.), allowing chemists to count particles by weighing samples. This concept is essential for quantifying the amount of a substance and for performing stoichiometric calculations in chemical reactions.

Transcript

00:01 In this video we will study about conversions.

00:09 So conversions will be from grams to moles and atoms to moles.

00:20 So let's start with the first problem set.

00:29 So we are provided with 40 .1 gram of calcium.

00:35 Of calcium.

00:39 So before we solve it, let's write down the formula.

00:44 Now formula is, if we want to calculate number of moles, so let's write it down, number of moles, right, is equal to amount in grants, okay, and then divide it by grants present, present in one more okay or other way we can say is molar mass so number of moles is amount in grams divided by grams present in one mole or we can say molar mass so that is grams per mole for the specific element so let's solve this so for this problem said we are given the amount in grams so number of moles will be equal to this is 40 .1 gram okay so we'll write it down 40 .1 gram right into one mole divided by molar mass of calcium which is 40 .0 .7 7, 8 gram per mole.

03:04 So we have written one mole on the top.

03:07 So it's like amount in grams divided by number of grams present in one mole.

03:14 So our answer will be one more.

03:30 Okay.

03:30 So basically we will divide the amount in grams with the molar mass.

03:36 Let's do second problem set.

03:49 For second problem set, we are given.

03:51 11 .5 gram of sodium and our answer will be so 11 .5 gram divided by molar mass that is 22 .999 gram per mole.

04:17 That's number of grams per mole of sodium and our answer is 0 .5 more.

04:30 So basically we're dividing the weight in grams with the number of grams present in one mole and we will get our answer.

04:38 Let's move to the third problem set.

04:46 For third problem set again we are given in grams.

04:51 So that's 5 .87 gram of nickel so important thing is we should know the molar mass of nickel which we can also see from the periodic table so number of moles will be 5 .87 gram divided by 58 .693 gram per mole and our answer is 0 .1010 okay, simple divide the amount in grams with the molar mass that is 58 .693.

05:38 Let's move on to the next one.

05:45 So for fourth problem set, we are again given the amount in grams and it's a 150 gram of sulfur as is the symbol for selection.

06:13 So again to solve it we will divide 150 gram by the molar mass that is 32 .06 gram per mole and our answer is 4 .68 moles.

06:37 Okay, so this number is a round of number so you can always see up to what decimal point you want to.

06:45 Go let's move to the next problem set okay again we are provided in grams so it's 2 .65 gram of iron simple right so just divide 2 .65 gram with the molar mass that's 55 per mole and our answer is 0 .0475 moles okay let's move to the next one so sixth problem set now we are provided with 0 .070750 gram of silver okay okay ag is the symbol for silver element.

08:14 So we know what to do.

08:16 We will divide 0 .00750 gram with the molar mass of silver.

08:26 That is 107 .87 gram per mole...

Please give Ace some feedback