Question

In the reaction Ca 2 H2O -> Ca(OH)2 H2, if starting with 1.05 moles of Ca and 2.05 moles of water, which is the limiting reactant

Answer 1

Answer:

Water is the limiting reactant.

Explanation:

Hello.

In this case, for the reaction:

$Ca+2H_2O\rightarrow Ca(OH)_2+H_2$

Having the moles of both calcium and water, we compute the moles of hydrogen yielded by each reactant, considering the 1:1 and 2:1 mole ratios regarding calcium to hydrogen and water to hydrogen:

$n_{H_2}^{by\ Ca}=1.05molCa*\frac{1molH_2}{1molCa}=1.05molH_2\\ \\n_{H_2}^{by\ H_2O}=2.05molH_2O*\frac{1molH_2}{2molH_2O}=1.025molH_2$

Thus, since the water yields fewer moles of hydrogen we infer water is the limiting reactant whereas calcium is the excess one.

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