7.7.1: Practice Stoichiometry Part 3

Last updated
Save as PDF

Page ID: 236046

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

Exercise \(\PageIndex{1}\)

2 NO _(g) + O_{2 (g)} \(\rightarrow\) 2 NO₂_(g) \(\Delta H \)= – 114 kJ

Is the reaction above endothermic or exothermic? What is the energy change when 0.633 moles of NO react?

Answer: Exothermic. Energy change is – 36.1 kJ, meaning that 36.1 kJ of energy is released.

Exercise \(\PageIndex{1}\)

CaCO₃ _(s) \(\rightarrow\) CO₂_(g) + CaO _(s) \(\Delta H \)= + 192 kJ

Is the reaction above endothermic or exothermic? What is the energy change when 2.87 grams of CaCO₃ react?

Answer: Endothermic. Energy change is + 5.51 kJ, meaning that 5.51 kJ of energy is absorbed.

Exercise \(\PageIndex{1}\)

S₈ _(s) + 12 O_{2 (g)} \(\rightarrow\) 8 SO₃_(g) \(\Delta H \)= – 3166 kJ

Is the reaction above endothermic or exothermic? What is the energy change when 26.7 grams of SO₃ are produced?

Answer: Exothermic. Energy change is – 132 kJ, meaning that 132 kJ of energy is released.

Exercise \(\PageIndex{1}\)

2 HCl _(g) \(\rightarrow\) H₂_(g) + Cl₂_(g) \(\Delta H \)= + 185 kJ

Is the reaction above endothermic or exothermic? What is the energy change when 489 grams of HCl react?

Answer: Endothermic. Energy change is + 1240 kJ, meaning that 1240 kJ of energy is absorbed.