Question

How many grams of Li will be needed to produce 27.93 grams of LiOH upon reaction with H2O?

Answer 1

Well, you have been given the stoichiometric equation....

Explanation:

`Li(s) +H_2O(l)rarrLiOH(aq) + 1/2H_2(g)uarr`

And so address the molar quantities of the given product. We got a molar quantity WITH RESPECT to lithium hydroxide of...

`(27.93*g)/(23.95*g*mol^-1)=1.17*mol`...

And given the stoichiometry, CLEARLY there was a `1.17*mol` quantity of lithium metal....i.e. a mass of...

`1.17*molxx6.941*g*mol^-1=8.09*g`

Your letter option is clear, but this is not a terribly realistic question, inasmuch as it would be hard to isolate this lithium hydroxide as a dry powder....