Molar mass of NaCl and other compounds | Acemyhomework Writers
Molar mass of NaCl and othercompounds
Before we begin to calculate the molarmass of NaCl or any other compound for that matter, it is important that weknow what exactly the molar mass of an element is. We know that allthings around us are occupied by matter whose building block is molecules. Itbecomes essential that we measure these molecules in all the experiments to getaccurate results for our products in the experiment. Thus, a change in themolecular mass of a compound can greatly vary the results of anyscientific calculations. For all laboratory calculations, a tool calledthe analytical balance is used to measure the weights in grams. After variouscalculations and observations, a scientist discovers the number of molesrequired for a particular experiment based on which we calculate the molarmass. A mole is nothing, but a unit used for measurement which helps incomparing particles and mass of a given compound. Once we are aware of themoles required for a particular experiment, we can easily use the concept andnotion of molar mass for determining the grams of substance required for ourpurpose. The molar mass of a compound is also known as its molecular weight andis the total mass in grams of the atoms that form one mole of a certainmolecule. Its unit of measurement is g/mol. That is, the molar mass of a substance=1 gram/I mole
Calculating the molar mass of NaClcan be extremely simple only if you know the difference between elements andcompound and have a knowledge about the molecular weight of the respectiveelements. Compounds are basically substances that are formed when two or moreelements react chemically while elements, on the other hand, are naturallyoccurring substances found mostly in abundance on Earth or in the atmosphere.Let us take the example of the molar mass of NaCl. The compound NaCl iscomposed of two elements, sodium (Na) and Chlorine (Cl) and together when theyreact chemically, they form NaCl as the product. NaCl consists of a lattice ofNa+ and Cl- ions which react in the ratio of 1:1 to give us halite or salt.Scientifically known as Sodium Chloride and fondly referred to as common salt,NaCl is a compound responsible for making up the extracellular fluids in mostcellular organisms and causing the salinity in seawater. Its many applications includethat of a food preservative and for de-icing of pathways and highways. In fact,Sodium Chloride has a lot of industrial applications such as in the soda ashindustry or the chlor-alkali process and thus, knowing the molar mass of NaClis very important.
The very first thing whiledetermining the molar mass of a compound is to look at the molecular weight ofindividual elements in the periodic table. Sometimes it is very difficult tomemorize the atomic mass of the heavy elements and in such cases, it isbest to see a periodic table to get accurate results. Now, since the compoundNaCl is made of sodium and chlorine, the molar mass of NaCl can be calculatedonly after its atomic weight is known from the table. Individual atoms ofsodium and chlorine have an atomic mass of 22.98976 g/mol and 35.453 g/molrespectively. The next step towards calculating the molar mass of NaCl isdetermining the number of atoms for each element of the compound. For examplein NaCl, there are no subscripts or small numbers present at the bottom of theelements which means that both Na and Cl contribute a single atom to make NaCltogether. Had the compound been, say CaCl2, then the number of atoms forCalcium would have been one and that of Chlorine would have been two, based onthe subscript represented along with its symbol. After finding out about theatoms, we can easily find out the molar mass of NaCl or any other compound.Molar mass of an element= no of atoms X the atomic weight of each element. And,molar mass of the compound= the sum total of molar mass of all the elements.
That is, Sodium (Na) = 1 X 22.98=22.98 g/mol
Chlorine (Cl) = 1 X 35.45= 35.45g/mol
Molar Mass= (22.98 + 35.45) g/mol =58.44 g/mol
After calculating the atomic mass ofeach element and its individual atom, the molecular mass is determined whichcomes out to be around 58.44 after rounding off to the nearest decimal.
The need forcalculating the molar mass of NaCl or any other compound
Determining the molar mass of acompound is extremely essential in the field of chemistry. It forms the basis for all other calculations.This is because it helps the scientists to know how much mass is occupied by aquantity of matter. For any chemical reaction, it becomes extremely vital toknow the exact number of atoms that the scientists will be needing to carry outtheir research. Even a slight variation in the calculation can lead to drasticchanges in the field of chemistry. Moreover, even the tiniest substance is madeof a large number of atoms amounting to some billions and thus, to avoid anydiscrepancies scientists make use of the mole concept as a unit of measurement.
Now, the one mole of substance canbe defined as the number of atoms present in 12 grams of a carbon-12 atom. Thisquantity is scientifically known as the Avogadro’s number and its number comesout to be approximately 6.022 X 10^23. To sum up, a mole is nothing, but thetotal substance that has the same amount of molecules or atoms as that of a 12gram of a carbon-12 atom. For example, molar mass of NaCl will also contain asimilar number of atoms which means that it would weigh around 58 grams andhave 6.022 X 10^23 molecules. Just like each atom or ion of a particularelement has some mass, in a similar way each mole of a given substance willalso carry some mass. Thus, the atomic mass unit or amu of an element is itsatomic weight which is equal and similar in quantity to the mass occupied byone mole of that element.
Just like we calculated the molarmass of NaCl, in a similar manner we can determine the molar mass of any othercompound. All we have to do is memorize or look up for the atomic weight of allthe elements in the periodic table. It is important that we get familiar withthe periodic table in order to determine the position of the exact element withease. To become more acquainted with the concept, let us calculate the molarmass of a complex compound. Take for example, copper (II) sulphate pentahydrateor CuSO4.5H2O. Here we have to write down the atomic mass of all the elementsincluding those present in water. The atomic mass of Copper was found to be63.55 g/mol while that of sulphur, hydrogen and oxygen was 32.07, 1.008 and 16g/mol. The compound consisted of 9 atoms of oxygen (4 in sulphur and 5 fromwater) while hydrogen had a total of 10 atoms and the rest had one atom each.This was put in its
formula and the molar mass came outto be:
CuSO4.5H2O = 63.55 + 32.07 + 4X16 +5(2 X 1.00 + 16). That is, 249.70 g/mol is the molar mass of the respectivecompound.
Other uses of the molar mass of NaCl
By calculating the molar mass ofNaCl, we can easily determine the number of moles of NaCl or any othersubstance. The number of moles of a substance can be calculated by using thefollowing formula.
N=n/m ; Where, N= no of moles, n=number of grams of the substance and m= its molar mass; For example, if we wantto calculate the number of moles of NaCl in a particular gram we simply need tofigure out the molar mass of NaCl and the mass of the substance in grams. Likeif someone asks us to determine the number of moles in say, 72.33 grams ofNaCl. The molar mass of NaCl is 58.44g and thus, the number of moles can beeasily calculated.
That is, N= 72.33/58.44
N= 1.2376 mol
This means you have around 1.23 molof NaCl in 72.33 grams of it. Thus, the molar mass of NaCl can be used tocalculate molarity, normality etc.
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