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Course: AP®︎/College Chemistry > Unit 6

Lesson 5: Introduction to enthalpy of reaction

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Introduction to enthalpy of reaction

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You might need: Periodic table

Mg (s) + 2 HCl (a q) \to MgCl_{2} (a q) + H_{2} (g) {Δ H °}_{r x n} = - 470 {kJ/mol}_{r x n}

In an experiment, a student adds

100. mL

of

1.00 M HCl (a q)

to

2.43 g

of

Mg (s)

, resulting in the formation of a gas. The balanced equation for the reaction is shown above.

Which of the following shows the limiting reactant and the amount of heat released, $q$ ‍, for the experiment?

(Choice A)
$Limiting reactant$ ‍ $q$ ‍
$Mg$ ‍ $24 kJ$ ‍
(Choice B)
$Limiting reactant$ ‍ $q$ ‍
$Mg$ ‍ $47 kJ$ ‍
(Choice C)
$Limiting reactant$ ‍ $q$ ‍
$HCl$ ‍ $24 kJ$ ‍
(Choice D)
$Limiting reactant$ ‍ $q$ ‍
$HCl$ ‍ $47 kJ$ ‍

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