Answer:
They all have 7 valence electrons on it's outer shell.
Answer: 625 kj/mol
Explanation:
As shown below this expression gives the activation energy of the reverse reaction:
EA reverse reaction = EA forward reaction + | enthalpy change |
1) The activation energy, EA is the difference between the potential energies of the reactants and the transition state:
EA = energy of the transition state - energy of the reactants.
2) The activation energy of the forward reaction given is:
EA = energy of the transition state - energy of [ NO2(g) + CO(g) ] = 75 kj/mol
3) The negative enthalpy change - 250 kj / mol for the forward reaction means that the products are below in the potential energy diagram, and that the potential energy of the products, [NO(g) + CO2(g) ] is equal to 375 kj / mol - 250 kj / mol = 125 kj/mol
4) For the reverse reaction the reactants are [NO(g) + CO2(g)], and the transition state is the same than that for the forward reaction.
5) The difference of energy between the transition state and the potential energy of [NO(g) + CO2(g) ] will be the absolute value of the change of enthalpy plus the activation energy for the forward reaction:
EA reverse reaction = EA forward reaction + | enthalpy change |
EA reverse reaction = 375 kj / mol + |-250 kj/mol | = 375 kj/mol + 250 kj/mol = 625 kj/mol.
And that is the answer, 625 kj/mol
Answer:
a) 128 grams
b) 81.25%
Explanation:
a) The mixture will be between the alloy and the pure copper, so the mass will be the sum of the mass of the compounds:
m = 50 + 78 = 128 g
b) In the alloy, 52% is copper, so to know the mass of copper in the alloy, we must multiply the total mass by 52% (which is 0.52)
0.52x50 = 26 g of copper
The total mass of copper in the mixture is 26 + 78 = 104 g
So, the percentual of copper is the mass of copper divided by the total mass
104/128 = 0.8125
Multiplying by 100%, to have the result in percentage
0.8125x100% = 81.25%
You would calculate them by dividing them and then multiplying to get the final answer
