Question

How many milliliters of a \[2.6{\text{ }}M\] glucose solution contains \[0.86{\text{ }}moles\] ?

Answer 1

Hint:The mole concept is very significant and useful in chemistry. It is actually the base of stoichiometry and it provides the best option to express the amounts of reactants as well as products that are consumed and formed during a chemical reaction.

Complete step by step answer:
 In the question, we have to calculate the volume of the glucose solution and we are provided with the following parameters:
Molarity of glucose = \[2.6{\text{ }}M\]
Number of moles = \[0.86{\text{ }}moles\]
Volume of solution =$?$
Now, recall the basic concept of molarity. A solution's molarity tells you about the number of moles of solute that is present in 1 L of solution. You can say:
$Molarity(M) = \dfrac{{moles{\text{ }}of{\text{ solute}}}}{{1{\text{ }}litre{\text{ of }}solution{\text{ }}}}$
So, we will use the aforementioned formula of molarity to calculate the volume of solution in liters and we will later on convert it into the desired unit i.e. millilitres.
So now, we will substitute the all given values in the formula of molarity as shown below:
$
  Molarity(M) = \dfrac{{moles{\text{ }}of{\text{ }}solute}}{{volume{\text{ }}of{\text{ }}solution{\text{ }}(liters){\text{ }}}} \\
  2.6 = \dfrac{{0.86}}{{volume{\text{ }}of{\text{ }}solution{\text{ }}(liters)}} \\
  volume{\text{ }}of{\text{ }}solution{\text{ }}(liters) = \dfrac{{0.86}}{{2.6}} = 0.3307litres \\
$
Now we have got the volume of glucose solution in litres which we will convert it into millilitres by multiplying it with 1000 as shown below:
$Volume{\text{ }}of{\text{ }}solution{\text{ }}in{\text{ }}millilitres = 0.3307 \times 1000 = 330.7mL$
Hence, 330.7 milliliters of a \[2.6{\text{ }}M\] glucose solution contains \[0.86{\text{ }}moles\] .

Note: Don’t get confused between molarity and molality. Molarity is the number of moles of solute per volume of solution (litres) while Molality is the number of moles of solute per weight of solvent (kilogram). These two have a relationship as below:
Molality = (density of the solution − molarity) $\times$ molecular weight of solute molarity.