Question

How do you convert 2.54 moles magnesium carbonate to formula units?

Answer 1

Hint: Here we have to find the number of particles for the 2.54 moles of magnesium carbonate, which is estimated by multiplying the number of moles given with the Avogadro constant.

Complete step by step answer:
So in the question it is asked how do we convert the given moles of substance to formula units. Before going into the solution part let us first discuss what does formula unit means.
- The formula units are the simplest whole number ratio or can be said as the simplest elementary particle which cannot be subdivided and it is similar to the empirical formula of a compound which possesses an ionic bond.
- So the basic concept to solve the question is, one mole of a substance consists of Avogadro number $\left( {{N}_{A}} \right)$ of particles or Avogadro constant of particles
- The value of Avogadro number is $6.022\times {{10}^{23}}$, therefore one mole consists of $6.022\times {{10}^{23}}$ of particles (which can be atoms, ions, molecules).
So we can calculate the number of formula units for the given moles of substance by carrying out the multiplication operation with the value of the number of moles of magnesium carbonate and the Avogadro constant.
Since,$\text{1}\,\text{mole}\,\text{=}\,\text{6}\text{.022 }\!\!\times\!\!\text{ 1}{{\text{0}}^{\text{23}}}\text{particles}$
$\text{Number}\,\text{of}\,\text{moles}\,\text{of}\,\text{MgC}{{\text{O}}_{\text{3}}}\,\text{=2}\text{.54 moles}$
- We can write formulae as,
$\text{Number}\,\text{of}\,\text{formula}\,\text{units=Number}\,\text{of}\,\text{moles }\!\!\times\!\!\text{ }{{\text{N}}_{\text{A}}}$
Substitute the values in the given equation and we can calculate the final answer as,
$\text{Number}\,\text{of}\,\text{formula}\,\text{units=2}\text{.54 }\!\!\times\!\!\text{ 6}\text{.022}\times \text{1}{{\text{0}}^{23}}=1.5295\times {{10}^{24}}$
So there are $1.5295\times {{10}^{24}}$ formula units in 2.54 moles of magnesium carbonate.

Note: Here in the question, since the number of moles is given we must have to multiply the value with Avogadro number. But if only the weight of the compound was given, then we have to find the molar mass of the compound given and then we have to find the number of moles of the substance to carry out the calculation.
- And if the molar mass of the substance is given and have to find the formula units, then it consists of 1 mole of substance i.e. it consists of Avogadro number of formula units.