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If 58.27 g Ca react with 92.3 g HBr according to the reaction below, how many grams of hydrogen gas will be produced?

Unbalanced equation: Ca + HBr → CaBr2 + H2


Please HELP

User Hao Wu
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1 Answer

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The number of grams of hydrogen that will be produced is 1.142 grams


calculation

Step 1: write a balanced chemical equation

Ca + 2 HBr → CaBr₂ + H₂

Step 2: find the moles of each reactant

moles = mass /molar mass

The molar mass of Ca = 40 g/mol, for HBr = 1 + 79 .9 =80.9 g/mol

moles for Ca = 58.27 g /40 g/mol =1. 457 moles

moles for HBr = 92.3 g/ 80.9 g/mol =1.141 moles

Step 3: determine the limiting reactant

from equation above Ca :H2 is 1:1 therefore the moles of H₂ = 1.457 moles

HBr :H₂ is 2:1 therefore the moles of H₂ =1.141 moles x 1/2 =0.571 moles


since HBr produces least amount of H₂ it the limiting reactant and hence the moles of H₂ produced is 0.571 moles



Step 4: find the mass of H₂

mass = moles x molar mass

from periodic table the molar mass of H₂ = 2 g /mol

mass =0.571 x2 =1.142 grams



User Aashish Gaba
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