What mass of calcium hydride is obtained from a #5.0*g# mass of calcium metal?

1 Answer
Mar 16, 2017

Answer:

Approx. #5*g#................

Explanation:

Calcium hydride is formed by direct combination of its elements at elevated temperature:

#Ca(s) + H_2(g) rarr CaH_2(s)#

Given that the dihydrogen was in excess, moles of calcium hydride is equivalent to moles of calcium:

#"Moles of calcium"=(5.0*g)/(40.08*g*mol^-1)=0.125*mol#

Given the #1:1# stoichiometry, we form #0.125*mol# #CaH_2#, and this represents a mass of #0.125*cancel(mol)xx42.10*g*cancel(mol^-1)=5.25*g#.

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