Question

4. How much Heat will be released when 19 g of Hydrogen reacts with excess 02according to the following equation? 2H2 + O2 ---> H2OH = -580 kJ

Answer 1

-2733.13kJ (negative sign shows heat is given off)

Explanations:

Given the balanced chemical reaction between hydrogen and oxygen expressed as:

`2H_2+O_2\rightarrow2H_2O\text{ }\triangle H=-580kJ`

According to the reaction, 1 moles of hydrogen produces -580kJ

Determine the moles of Hydrogen gas

`\begin{gathered} mole=\frac{mass}{mole\text{ mass}} \\ mole\text{ of H}_2=\frac{19g}{2.016g\text{/mol}} \\ mole\text{ of H}_2=9.42moles \end{gathered}`

Determine the heat released by 9.42moles of hydrogen

`\begin{gathered} \triangle H_{rxn\text{ for 19g of H}2}=9.42\cancel{moles\text{ H}_2}*-\frac{580kJ}{2\cancel{mole\text{ H}_2}} \\ \triangle H_{rxn\text{ for 19g of H}2}=-2733.13kJ \end{gathered}`

This shows that about 2733.13kJ of heat will be given off