This is my first post on this forum and I have noticed that there are most likely people who can help me understand some very basic concepts of chemistry. I am currently studying grade 12 AP chemistry, and I can solve most problems at this level with ease. However, I am having difficulty understanding why some things work the way they do.
First, I don't understand how to predict which compounds would give an acidic aqueous solution and which ones would give a basic aqueous solution. People seem to be able to tell right away, but I certainly can't. I understand how the measure of acidity works, how it is the log of the concentration of hydrogen ions, but let me give an example to explain my confusion:
I have heard that KCN, when dissolved in water, would give a basic aqueous solution. Why is this? I recognize that KCN will ionize into separate K+ and CN- ions. What I don't understand is how that will change the pH. In water, there are H+ and OH- ions which neutralize eachother and explain the neutral pH of 7. however, how does the addition of KCN affect this?
I mean, I understand when something like NaOH is added and why that augments the pH, because that is a direct OH- addition and in the above case there is no such thing. Can someone please explain that to me thoroughly?
Second, and this is a very specific question: Does the speed or weight of photons have anything to do with how energetic the corresponding radiation is?
X-ray radiation is more energetic than microwave radiation only because x-ray radiation has a higher frequency than does microwave radiation. Am I right about this? The characteristics of the photon pertaining to this question are irrelevant, right?
If that sounded confusing, then the specific problem I was looking at was:
X-ray radiation is more energetic than microwave radiation because:
A) photons of x-ray radiation travel faster than those of microwave radiation
B) photons of x-ray radiation are heavier than those of microwave radiation
C) x-ray radiation has a higher frequency than does microwave radiation
D) x-ray radiation has a longer wavelength than does microwave radiation
E) photons of x-ray radiation travel slower than those of microwave radiation
Thirdly, another question that I had is just why is radiation bad (to humans)? how are these electromagnetic waves, in some cases, so destructive?
Any help will be greatly appreciated. This isn't for any particular assignment or task, I just want to understand why and how some things work in chemistry.
Thanks in advance.