<u>Answer:</u> The equations are provided below.
<u>Explanation:</u>
Skeleton equations are defined as the equations which simply indicate the molecules that are involved in a chemical reaction. These equations are unbalanced equations.
Balanced equations are defined as the chemical equation in which number of individual atoms on the reactant side must be equal to the number of individual atoms on the product side.
Water decomposes in the direct current to form hydrogen and oxygen.
Skeleton Equation: 
Balanced Equation: 
Mercury (II) oxide decomposes in heat to form mercury, oxygen.
Skeleton Equation: 
Balanced Equation: 
Calcium carbonate when heated forms calcium oxide and carbon dioxide.
Skeleton Equation: 
Balanced Equation: 
Group 2 hydroxides, when heated forms oxide and water vapor.
Skeleton Equation: 
Balanced Equation: 
The radioactive decay obeys first order kinetics
the rate law expression for radioactive decay is
![ln\frac{[A_{0}]}{[A_{t}]}=kt](https://tex.z-dn.net/?f=ln%5Cfrac%7B%5BA_%7B0%7D%5D%7D%7B%5BA_%7Bt%7D%5D%7D%3Dkt)
Where
A0 = initial concentration
At = concentration after time "t"
t = time
k = rate constant
For first order reaction the relation between rate constant and half life is:

Let us calculate k
k = 0.693 / 72 = 0.009625 years⁻¹
Given
At = 0.25 A0

time = 144 years
So after 144 years the sample contains 25% parent isotope and 75% daughter isotopes**
Simply two half lives
Answer:
During ice ages, the most characteristic change to the planet has been the formation and spread large ice sheets and glaciers across much the Northern Hemisphere.
Main Answer:
Given
pH = -log[H+]
= -log[0.00017]
= 3.769
We know that
pW = pH + pOH
and pW =14
pOH = 14-pH
=14-3.769
=10.231
According to the definition
pOH = -log[OH-]
10.231 = log[OH-]-1
[OH-]= 5.87 x 10-11
Explanation:
What is pH?
pH is defined as the concentration of H+ ion in the solution. If the pH value is less than 7, then the solution will be acidic. If the pH value is greater than 7, then the solution will be basic.
To know more about pH, please visit:
brainly.com/question/8758541
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Hope this helps :) remember your conversions and just practice it's fairly easy:)