Answer: The activation energy is 10 kJ and the reaction is exothermic.
Explanation: Exothermic reactions are those in which heat is released and thus the energy of products is less than the energy of reactants.
Endothermic reactions are those in which heat is absorbed and thus the energy of products is more than the energy of reactants.
Activation energy is the extra amount of energy required by the reactants to cross the energy barrier to convert to products.
Given : Energy of reactants = 40kJ
Energy of activation: (50-40)=10 kJ
Energy of products = 50 kJ
Energy of products = 15 kJ
Thus Energy of products (15kJ) < Energy of reactants(40kJ), the reaction is exothermic as energy has been lost to surroundings in the form of heat.
Answer : The total mass of oxygen gas released in the reaction will be, 12.8 grams
Explanation :
Law of conservation of mass : It states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.
This also means that total mass on the reactant side must be equal to the total mass on the product side.
The balanced chemical reaction will be,
According to the law of conservation of mass,
Total mass of reactant side = Total mass of product side
Total mass of 
= Total mass of 
or,
Total mass of = Mass of 
+ Mass of 
As we are given :
Total mass of 
= 16.12 grams
The mass of 
= 9.72 grams
So,
Total mass of = Mass of + Mass of
Therefore, the total mass of oxygen gas released in the reaction will be, 12.8 grams
It belongs to the noble gas family
Answer:
3Cu(NO3)2 + 2Al —> 2Al(NO3)3 + 3Cu
Explanation:
From the question given above,
Copper (II) nitrate reacts with aluminum to form aluminum nitrate and copper. This can be obtained represent as follow:
Cu(NO3)2 + Al —> Al(NO3)3 + Cu
Thus, we can balance the above equation as follow:
Cu(NO3)2 + Al —> Al(NO3)3 + Cu
There are 2 atoms of N on the left side and 3 atoms on the right side. It can be balance by putting 3 in front of Cu(NO3)2 and 2 in front of Al(NO3)3 as shown below:
3Cu(NO3)2 + Al —> 2Al(NO3)3 + Cu
There are 3 atoms of Cu on the left side and 1 atom on the right side. It can be balance by putting 3 in front Cu as shown below:
3Cu(NO3)2 + Al —> 2Al(NO3)3 + 3Cu
There are 2 atoms of Al on the right side and 1 atom on the left side. It can be balance by putting 2 in front of Al as shown below:
3Cu(NO3)2 + 2Al —> 2Al(NO3)3 + 3Cu
Thus, the equation is balanced.
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