Question

If 16.4 g of calcium nitrate is heated. Calculate the volume of $N{{O}_{2}}$ obtained and mass of CaO obtained.
$2Ca{{(N{{O}_{3}})}_{2}}\to 2CaO+4N{{O}_{2}}+{{O}_{2}}$

Answer 1

Calcium nitrate decomposes and forms two moles of calcium oxide, four moles of nitrogen dioxide and one mole of oxygen. Calcium oxide (CaO) is a solid, nitrogen dioxide ($N{{O}_{2}}$) as a liquid when cooled and oxygen (${{O}_{2}}$) is a gaseous substance formed when calcium nitrates decompose.

Complete step by step solution:
In the question, it is given that 16.4 gm of calcium nitrate is heated.
The given chemical reaction is as follows.
$2Ca{{(N{{O}_{3}})}_{2}}\to 2CaO+4N{{O}_{2}}+{{O}_{2}}$
Molar mass of $Ca{{(N{{O}_{3}})}_{2}}$= 40 + 2 (14) + 6 (16) = 164.
Number of moles of

& Ca{{(N{{O}_{3}})}_{2}}=\dfrac{given\text{ }weight}{molecular\text{ }weight\text{ }of\text{ }the\text{ }subs\tan ce} \\\ & \text{ = }\dfrac{16.4}{164}=0.1 \\\ \end{aligned}$$ From the given equation we can say that 2 moles $$Ca{{(N{{O}_{3}})}_{2}}$$gives 4 moles of $$N{{O}_{2}}$$. Therefore 0.1 moles of $$Ca{{(N{{O}_{3}})}_{2}}$$is undergoing decomposition and gives 0.2 moles of $$N{{O}_{2}}$$. Volume of $$N{{O}_{2}}$$at STP $$\begin{aligned} & \text{=number of moles of N}{{\text{O}}_{\text{2}}}\text{ }\\!\\!\times\\!\\!\text{ volume in liter} \\\ & \text{=0}\text{.2}\times \text{22}\text{.4} \\\ & \text{= 4}\text{.48L} \\\ \end{aligned}$$ 2 moles of $$Ca{{(N{{O}_{3}})}_{2}}$$ gives 2 moles of CaO (from the given chemical reaction). Then 0.1 moles of $$Ca{{(N{{O}_{3}})}_{2}}$$gives 0.1 moles of CaO. Therefore mass of Calcium oxide (CaO) $$\begin{aligned} & \text{= number of moles of CaO }\\!\\!\times\\!\\!\text{ molecular weight of CaO} \\\ & \text{= 0}\text{.1}\times \text{56} \\\ & \text{=5}\text{.6g} \\\ \end{aligned}$$ **Therefore 16.4 g of calcium nitrate decomposes and forms 4.48 litre of $$N{{O}_{2}}$$ and 16.4 g of calcium nitrate decomposes and forms 5.6 g of Calcium oxide (CaO).** **Note:** Calcium nitrate decomposes and forms nitrogen oxides later those nitrogen oxides can be converted to nitric acid. Calcium nitrate is mostly produced as a fertilizer and used as nutrition for plants and in the treatment of wastewater. Calcium nitrate is a good source of calcium and nitrogen for plants.