Please show work:
Question below

b) 2.0 mol

Explanation:

Given data:

Number of moles of Ca needed = ?

Number of moles of water present = 4.0 mol

Solution:

Chemical equation:

Ca + 2H₂O     →      Ca(OH)₂ + H₂

now we will compare the moles of Ca and H₂O .

                          H₂O        :        Ca                

                             2           :        1

                             4.0           :       1/2×4.0 = 2.0 mol

Thus, 2 moles of Ca are needed.      

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