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

Water is the limiting reactant.

Step-by-step 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*(1molH_2)/(1molCa)=1.05molH_2\\ \\n_(H_2)^(by\ H_2O)=2.05molH_2O*(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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