Which of the following is the formation reaction for CaO(s) ?
can you check my answer(the one that has star next to it)
A. Ca(s) + 1/2O2(g)= CaO(s).
B. CaO(s)= Ca(s) + 1/2O2(g)
C. Ca2+(aq) + O2–(aq)= CaO(s)
D. 2 Ca(s) + O2(g)= 2CaO(s) (*)
E. 2 CaO(s)= 2 Ca(s) + O2(g)
Yes, D looks fine. Why is A not correct as the reactants and product are correct and it balances in terms of atoms?
I think A is the correct answer as it gives the heat of formation for one mole. D gives the heat of formation for two moles.
A is probably not correct because the coefficent(1/2) is not a whole number
A is correct for 1mol of CaO
To determine the formation reaction for CaO(s), we need to identify the balanced chemical equation that represents the formation of CaO(s) from its constituent elements.
The formation reaction is usually written in the form of the elements combining to form the compound without any coefficients. Let's analyze each option:
A. Ca(s) + 1/2O2(g) = CaO(s)
This equation represents the formation of CaO(s) but with a coefficient of 1/2 in front of O2(g), which is not balanced. Therefore, this is not the correct formation reaction.
B. CaO(s) = Ca(s) + 1/2O2(g)
This equation represents the decomposition of CaO(s) into Ca(s) and 1/2O2(g), which is the reverse of the formation reaction. Therefore, this is not the correct formation reaction.
C. Ca2+(aq) + O2–(aq) = CaO(s)
This equation represents ions combining to form CaO(s), which is not the formation reaction involving the elements. Therefore, this is not the correct formation reaction.
D. 2 Ca(s) + O2(g) = 2CaO(s) (*)
This equation represents the formation of 2CaO(s) from 2 Ca(s) and O2(g), with the coefficients properly balanced. Therefore, this is the correct formation reaction for CaO(s).
E. 2 CaO(s) = 2 Ca(s) + O2(g)
This equation represents the decomposition of 2CaO(s) into 2 Ca(s) and O2(g), which is the reverse of the formation reaction. Therefore, this is not the correct formation reaction.
Therefore, option D, 2 Ca(s) + O2(g) = 2CaO(s), is the correct formation reaction for CaO(s).