Question

How many molecules are in 4 grams of NaCl ?​

Answer 1

4.117703084×10²² molecule

Step-by-step explanation:

According to the definition of the mole which is a unit of amount of substance which contains exactly 6.02214076×10²³ (Avogadro's Number
`N_A`)elementary entities

The formula of calculating number of moles for a given mass of a specified chemical species:


`Mole = \frac{Mass}{Molar_{} Mass}`

Where Molar mass: the mass in grams of one mole of the compound (unit is g/mol or gram/mole)

The formula of calculating number of particles for a given number of moles:


`Number-of - particles = Moles * 6.02214076 * 10^(23)`

So, to calculate the moles of NaCl, we need to calculate the molar mass first

The molar mass of NaCl = Molar mass of Cl + Molar mass of Na = 35.5 + 23 = 58.5 g/mol

No. of moles in 4 grams of NaCl = 4/58.5 = 0.0684 moles

Then, We calculate the number of molecules in 0.0684 moles of NaCl
Which =

0.0684 × 6.02214076×10²³ = 4.117703084×10²² molecule

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