Answer: 40.1%
Explanation: The mass of calcium in this compound is equal to 40.1 grams because there's one atom of calcium present and calcium has an atomic mass of 40.1 . The molar mass of the compound is 100.1 grams. Using the handy equation above, we get: Mass percent = 40.1 g Ca⁄100.1 g CaCO3 × 100% = 40.1% Ca.
The question is incomplete. The complete question is :
Hydrogen is manufactured on an industrial scale by this sequence of reactions:
The net reaction is :
Write an equation that gives the overall equilibrium constant 
in terms of the equilibrium constants 
and 
. If you need to include any physical constants, be sure you use their standard symbols, which you'll find in the ALEKS Calculator.
Solution :
![$K_1 = \frac{[CO][H_2]^3}{[CH_4][H_2O]}$](https://tex.z-dn.net/?f=%24K_1%20%3D%20%5Cfrac%7B%5BCO%5D%5BH_2%5D%5E3%7D%7B%5BCH_4%5D%5BH_2O%5D%7D%24)
...............(1)
![$K_2 = \frac{[CO_2][H_2]}{[CO][H_2O]}$](https://tex.z-dn.net/?f=%24K_2%20%3D%20%5Cfrac%7B%5BCO_2%5D%5BH_2%5D%7D%7B%5BCO%5D%5BH_2O%5D%7D%24)
...................(2)
![$K=\frac{[CO_2][H_2]^4}{[CH_4][H_2O]^2}$](https://tex.z-dn.net/?f=%24K%3D%5Cfrac%7B%5BCO_2%5D%5BH_2%5D%5E4%7D%7B%5BCH_4%5D%5BH_2O%5D%5E2%7D%24)
On multiplication of equation (1) and (2), we get
![$K_1 \times K_2=\frac{[CO][H_2]^3}{[CH_4][H_2O]} \times \frac{[CO_2][H_2]}{[CO][H_2O]}$](https://tex.z-dn.net/?f=%24K_1%20%5Ctimes%20K_2%3D%5Cfrac%7B%5BCO%5D%5BH_2%5D%5E3%7D%7B%5BCH_4%5D%5BH_2O%5D%7D%20%5Ctimes%20%5Cfrac%7B%5BCO_2%5D%5BH_2%5D%7D%7B%5BCO%5D%5BH_2O%5D%7D%24)
![$K_1K_2=\frac{[CO_2][H_2]^4}{[CH_4][H_2O]^2}$](https://tex.z-dn.net/?f=%24K_1K_2%3D%5Cfrac%7B%5BCO_2%5D%5BH_2%5D%5E4%7D%7B%5BCH_4%5D%5BH_2O%5D%5E2%7D%24)
.................(4)
Comparing equation (3) and equation (4), we get
Answer : During chemical changes only.
Explanation : A chemical change is usually when a compound or molecule undergoes a change which is normally irreversible and it generates a new product than it was before.
So, when we consider the process of making up of substances from atoms it makes the substance as an irreversible product.
Also a new product which is formed is the substance which is not at all similar to atoms.
