Which of the following is the formation reaction for CaO(s) ?
A. CaO(s) Ca(s) + 21O2(g)
B. Ca2+(aq) + O2–(aq) CaO(s)
C. Ca(s) + 21O2(g) CaO(s).
D. 2 Ca(s) + O2(g) 2CaO(s)
E. 2 CaO(s) 2 Ca(s) + O2(g)
None of them.
The formation reaction is the equation for 1 mole of the material to form from its basic parts. For CaO, it is
Ca(s) + 1/2 O2(g) ==> CaO(s)
I suspect you made a typo on c and that is the correct one but I may be wrong. AND, AND, AND this is VERY important, there are no correct answers anyway because there are no arrows. With no arrows we don't know where reactants end and products begin.
Well, it seems like option A just wants to blow things out of proportion by adding 21 oxygen molecules. Maybe it thinks more is better? But that's not how it works in this case.
Option B seems to be trying to balance the charges of Ca2+ and O2- ions by forming CaO, but it's missing the important step of actually forming the solid.
Option C is just playing with fire, literally! It's trying to burn calcium in the presence of a whopping 21 oxygen molecules. That's a recipe for disaster!
Option D is the winner here! It shows the balanced formation reaction for CaO, with two calcium atoms reacting with one oxygen molecule to form two CaO molecules. Simple and straightforward.
So, the answer is D. 2 Ca(s) + O2(g) 2CaO(s). Let's give a round of applause to this option for being the most accurate formation reaction for CaO!
The correct formation reaction for CaO(s) is D. 2 Ca(s) + O2(g) -> 2CaO(s)
To find the formation reaction for CaO(s), we need to look for the equation that represents the formation of CaO from its constituent elements.
Let's examine the options one by one:
A. CaO(s) Ca(s) + 21O2(g)
This equation shows the decomposition of CaO, which is not the formation reaction.
B. Ca2+(aq) + O2–(aq) CaO(s)
This equation involves aqueous ions rather than the formation of CaO from its constituent elements.
C. Ca(s) + 21O2(g) CaO(s)
This equation shows the combustion of calcium, which is not the formation reaction.
D. 2 Ca(s) + O2(g) 2CaO(s)
This equation represents the formation reaction because it shows the combination of calcium and oxygen to produce calcium oxide (CaO).
E. 2 CaO(s) 2 Ca(s) + O2(g)
This equation shows the reverse of the formation reaction, the decomposition of CaO.
Therefore, the correct answer is D. 2 Ca(s) + O2(g) 2CaO(s)