Half-life time of a reaction is time at which reactant concentration becomes half of its initial value.
Half-life of the first order reaction is 20 min. Rate constant can be calculated as follows:
The rate expression for first order reaction is as follows:
initial number of molecules of reactant are 
, time is 100 min thus, putting the values to calculate number of reactant at time 100 min,
![0.03466 min^{-1}=\frac{2.303}{100 min}log\frac{[10^{20}]}{A_{t}}](https://tex.z-dn.net/?f=0.03466%20min%5E%7B-1%7D%3D%5Cfrac%7B2.303%7D%7B100%20min%7Dlog%5Cfrac%7B%5B10%5E%7B20%7D%5D%7D%7BA_%7Bt%7D%7D)
On rearranging,
Or,
Therefore, number of molecules unreacted will be 
<span>For the answer to the question above,
If 3g of element combines with 8g of D to form CD it means
1 mole of C = 3g
1 mole of D = 8g
hence it forms CD.
So to form CD2 you need 16g of element D
I hope my answer helped you</span>
Chemicals dissolved in water. Calcite is a good example, if I'm not mistaken.
Answer:
Explanation:
the forces between the molecules are stronger in solid than in liquids
