Answer : The enthalpy change for the reaction is, 419.5 kJ
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
The given chemical reaction is,
Now we have to determine the enthalpy change for the reaction below:
By reversing and then dividing the reaction by 2, we get the enthalpy change for the reaction.
The expression will be:
Therefore, the enthalpy change for the reaction is, 419.5 kJ
kg and all the given units are units used to measure mass.
kg is the standard unit to measure mass
lets find the value of 0.00684 kg in all the given units
a. dkg
1 kg is equivalent to 100 decagram (dkg)
therefore 0.00684 kg is = 100 dkg/kg x 0.00684 kg = 0.684 dkg
this is not the given value therefore this choice is incorrect
b. 1 kg is equivalent to 1000 g
therefore 0.00684 kg = 1000 g/kg x 0.00684 kg = 6.84 g
this is the given value so this is correct
c. 1 kg is equivalent to 100 000 centigrams (cg)
therefore 0.00684 kg = 100 000 cg/kg x 0.00684 kg = 684 cg
this is the given value so this is also correct
d) 1 kg is equivalent to 1 000 000 mg
therefore 0.00684 kg = 1 000 000 mg/kg x 0.00684 kg = 6 840 mg
this too is correct
the incorrect answer is A. 0.0684 dkg
When a atom loses electrons it becomes a ion
Explanation:
A catalyst lowers the activation energy of a reaction allowing them to proceed faster than they would naturally. Activation energy is the free energy that is required to be input in the reactant side to activate them to the transition state after which the reaction proceeds spontaneously to products.
An example of a catalyst is platinum, that is put in the exhaust of cars, to help convert carbon monoxide to carbon dioxide before it is emitted into the air.
Answer:
the experimental variable
Explanation:
