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3 years ago

Suppose a snack bar is burned in a calorimeter and heats 2,000 g water by 20 °C. How much heat energy was released?

Chemistry

1 answer:

prohojiy [21]3 years ago

7 0

Heat energy released : 167.2 kJ

<h3>Further explanation</h3>

Heat can be calculated using the formula:

Q = mc∆T

Q = heat, J

m = mass, g

c = specific heat, joules / g ° C

∆T = temperature difference, ° C / K

m = 2000 g

c = 4.18 J/ g ° C

∆t = 20 ° C

$\tt Q=2000\times 4.18\times 20\\\\Q=167200~J=167.2~kJ$

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Reduction reaction : It is the reaction in which a substance gains electrons. In this oxidation state decreases.

The given unbalanced chemical reaction is,

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Half reactions of oxidation and reduction are :

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Reduction : $2I^-(aq)+2e^-\rightarrow I_2$ .......(2)

In order to balance the electrons, we multiply equation 1 by 2 and equation 2 by 3, we get:

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