<span>
</span><span>7/9 x 45/1 = 7/1 x 5/1
by dividing both sides by 9
7/1 x 5/1 = 35/1 = 35</span>
Answer:
The answer to the question is
50 % of the original amount of potassium 40 will be left after one half life or 1.25 billion years
Explanation:
To solve the question we note that the half life is the time for half of the quantity of substance that undergoes radioactive decay to disintegrate, thus
we have
half life of potassium 40 K₄₀ = 1.25 billion years
To support the believe tht the rock was formed 1.25 billion years ago we have

After 1.25 billion years we have
=
=0.5 of
will be left or 50 % of the original amount of potassium 40 will be left
Explanation:
It is known that for first order reaction, the equation is as follows.
t = ![\frac{2.303}{K} log \frac{[C_{4}H_{8}]_{o}}{[C_{4}H_{8}]_{t}}](https://tex.z-dn.net/?f=%5Cfrac%7B2.303%7D%7BK%7D%20log%20%5Cfrac%7B%5BC_%7B4%7DH_%7B8%7D%5D_%7Bo%7D%7D%7B%5BC_%7B4%7DH_%7B8%7D%5D_%7Bt%7D%7D)
t = ?, K = rate constant = 79 1/s
Initial conc. of
= 1.68
Decompose amount of
= 52% of 1.68
= 
= 0.8736
= 0.87
Now,
= (1.68 - 0.87)
= 0.81
Therefore, calculate the value of t as follows.
t = ![\frac{2.303}{K} log \frac{[C_{4}H_{8}]_{o}}{[C_{4}H_{8}]_{t}}](https://tex.z-dn.net/?f=%5Cfrac%7B2.303%7D%7BK%7D%20log%20%5Cfrac%7B%5BC_%7B4%7DH_%7B8%7D%5D_%7Bo%7D%7D%7B%5BC_%7B4%7DH_%7B8%7D%5D_%7Bt%7D%7D)
= 
= 
=
s
= 
Thus, we can conclude that 0.00921 s will be taken for 52% of the cyclobutane to decompose.
The net ionic equation of the reaction is:
- Pb²⁺ (aq) +2 I⁻ (aq) → PbI2(s)
<h3>What are net ionic equations?</h3>
Net ionic equations are equations where ions which remain in solution known as spectator ions are not shown in the equation. Only ions involved in formation of product are shown.
In the given equation, sodium and nitrate ions are spectator ions.
The net ionic equation of the given reaction is as follows:
- Pb²⁺ (aq) +2 I⁻ (aq) → PbI2(s)
In conclusion, spectator ions are not shown in net ionic equation.
Learn more about net ionic equations at: brainly.com/question/19705645
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