The doctor required a 15% 750mL solution. To lower the concentration of the solution, you have to add more diluting liquid.
750mL * 0.15 = 112.5mL. This 112.5mL signifies the pure chemical or compound in the solution. This 112.5mL can be taken from the stock solution.
112.5 * 2 = 250mL of stock solution would be needed and 500 mL of the diluting agent should be added. Adding the two together would result to a 750mL solution of 15% concentration.
negative charge is electron
positive charge is a proton
no charge is neutron
The 3 indicates the third electron shell. (Which has only 1 electron in it in this configuration)
Hope this helps! :)
Answer:

Explanation:
Hello there!
Unfortunately, the question is not given in the question; however, it is possible for us to compute the equilibrium constant as the problem is providing the concentrations at equilibrium. Thus, we first set up the equilibrium expression as products/reactants:
![K=\frac{[NO_2]^2}{[NO]^2[O_2]}](https://tex.z-dn.net/?f=K%3D%5Cfrac%7B%5BNO_2%5D%5E2%7D%7B%5BNO%5D%5E2%5BO_2%5D%7D)
Then, we plug in the concentrations at equilibrium to obtain the equilibrium constant as follows:

In addition, we can infer this is a reaction that predominantly tends to the product (NO2) as K>>>>1.
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