Question

If 10.0 grams of lithium hydroxide react as shown in the equation above, how many grams

Answer 1

Answer:

32.5g

       

Explanation:

Given parameters:

Mass of lithium hydroxide  = 10g

Unknown:

Mass of lithium bromide produced  = ?

Solution:

The equation of the reaction is shown below;

          LiOH     +    HBr  →   LiBr    +   H₂O

This is an acid-base type of reaction called neutralization.

To solve this problem, work from the known specie to the unknown. The known specie here is LiOH.

Find the number of moles of LiOH;

        Number of moles of LiOH = $\frac{mass}{molar mass}$

Molar mass of LiOH  = 7 + 16 + 1  = 24g/mol

    Number of moles  = $\frac{10}{24}$ = 0.42moles

Now,

From the balanced chemical equation;

                 1 mole of LiOH produced 1 mole of LiBr

                0.42 moles of LiOH will produce  0.42 moles of LiBr

To find the mass of LiBr produced;

              Mass of LiBr = number of moles x molar mass

Molar mass of LiBr  = 7 + 80  = 87g/mol

             Mass of LiBr  = 0.42 x 87  = 32.5g