Answer to Question #160712 in Chemistry for Sascha

Question

calcium is a group 2 metal which reacts with nitric acid according to the balanced symbol equation:

Ca + 2HNO3 - Ca (NO3)2 + H2

(relative atomic mass: H=1 N=14 0=16 Ca=40

0.2g of calcium metal was reacted with excess nitric acid. calculate the volume of hydrogen gas which was produced in this reaction

Answer 1

Solution:

The balanced chemical equation:

Ca(s) + 2HNO₃(aq) → Ca(NO₃)₂(aq) + H₂(g)

According to the equation above: n(Ca) = n(H₂)

Moles of Ca = Mass of Ca / Molar mass of Ca

The molar mass of Ca is 40 g mol^-1.

Hence,

n(Ca) = 0.2 g / 40 g mol^-1 = 0.005 mol

n(H₂) = n(Ca) = 0.005 moles

At STP, one mole of any gas occupies a volume of 22.4 L.

Thus 0.005 mol of H₂ occupies:

(0.005 mol × 22.4 L) / 1 mol = 0.112 L of H₂ = 112 mL of H₂

V(H₂) = 0.112 L = 112 mL.

Answer: 112 mL of hydrogen gas (H₂) was produced in this reaction.