<u>Answer:</u> The chemical equation for the given reaction is given below.
<u>Explanation:</u>
When solid calcium oxide reacts with sulfur trioxide gas to produce solid calcium sulfate, the chemical equation follows:

This is the reaction when a metal oxide reacts with non-metal oxide to produce a salt.
By Stoichiometry of the reaction:
1 mole of solid calcium oxide reacts with 1 mole of sulfur trioxide gas to produce 1 mole of solid calcium sulfate.
Yo sup??
Let the percentage of K-39 be x
then the percentage of K-40 is 100-(x+0.01)
We know that the net weight should be 39.5. Therefore we can say
(39*x+40*(100-(x+0.01))+38*0.01)/100=39.5
(since we are taking it in percent)
39*x+40*(100-(x+0.01))+38*0.01=3950
39x+4000-40x-0.4+0.38=3950
2x=49.98
x=24.99
=25 (approx)
Therefore K-39 is 25% in nature and K-40 is 75% in nature.
Hope this helps.
I would say A but I am not sure
Using the chart that has been provided, we may determine water temperature. We do this by drawing a straight line form the bottom scale which has the ppm of oxygen dissolved to the middle scale which has the percentage saturation.
The line starts from 11.5 ppm on the bottom scale and goes to 90% on the middle scale. Next, we continue this line, without changing its slope, to the third scale showing temperature. We see that it crosses the temperature scale at 4°C.
The temperature of the water is 4 °C.