B. One
I believe that earth is the only planet that has life that we know of on it.
Answer:
Approx. 20 moles of iron.
Explanation:
There are approx. 6.022 x 10.23 iron atoms per mole of iron. In this quantity, The number of iron atoms has a mass of
55.85 ⋅ g.
Answer:
Reaction A, B, E and F are exothermic reactions.
Explanation:
Exothermic reactions are defined as the reactions in which energy of reactants is more than the energy of the products. In these reactions, energy is released by the system.
The total enthalpy of the reaction
comes out to be negative.
Endothermic reactions are defined as the reactions in which energy of products is more than the energy of the reactants. In these reactions, energy is absorbed by the system.
The total enthalpy of the reaction
comes out to be positive.
So, from the given option reaction which are exothermic are with negative value
that enthalpy of reaction and those are:
1)
,ΔH = -1203 kJ/mol
2)
,ΔH =-176 kJ/mol
3)
,ΔH = -393.5 kJ/mol
4)
,ΔH =-891 kJ/mol
D but if I’m wrong my apologies