There you go , This is my work i have did on that subject area
The correct answer would have to be true
The percentage of Chromium in Chromium Oxide is calculated as follow,
Step 1: Calculate Molar mass of Cr₂O₃,
Cr = 51.99 u
O = 16 u
So,
2(51.99) + 3(16) = 103.98 + 48 = 151.98 u
Step 2: Secondly divide molar mass of only chromium with total mass of Cr₂O₃ and multiply with 100.
i.e.
=

× 100
=
68.41 %
So, the %age composition of chromium in chromium oxide is
68.41 %.
511.2 grams of chlorine gas consumed (with excess H-) when
1,342.0 kJ of energy is released from the system.
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What is an exothermic reaction?</h3>
In thermochemistry, an exothermic reaction is a "reaction for which the overall standard enthalpy change ΔH⚬ is negative."
Given that 1 mole of chlorine releases -184.6 energy.
Then, we have to find the number of moles of chlorine when 1,342.0 kJ of energy is released from the system.
So, calculating number of moles of chlorine.
Moles = 
Moles = 7.2 mole
Now, calculating number mass of chlorine.

Mass = 7.2 mole x 71 g/mole
Mass = 511.2 gram
Learn more about exothermic reaction here:
brainly.com/question/10373907
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