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When two or more substances combine, they create one or more new substances, which sometimes have different molecular structures from the original substances, meaning they absorb and radiate light in different ways, leading to a color change.
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There is no path of electrons around the nucleus. There are however things called orbitals where you are likely to find electrons.
Answer:
As with the hydrogen-ion concentration, the concentration of the hydroxide ion can be expressed logarithmically by the pOH. The pOH of a solution is the negative logarithm of the hydroxide-ion concentration. pOH=−log[OH−] The pH of a solution can be related to the pOH.
We have a 3-colour vision which happens to be the primary colours: red, blue and yellow. So, we can see red, and that is why we see it.
To see other we just mix the different cells as if we where mixing paint to get a new colour.
Hope it was easy to understand,
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