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studiot last won the day on May 9

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About studiot

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    Somerset, England
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    applications of physical sciences
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    Retired Technical Consultant

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  1. As I see it, @popcornfrenzy has not yet told us the entire question, as it is writen in the book or wherever. How do we know that we have to calculate a number of milligrams ? This was nowhere stated in the supposed complete copy of the question. I have suggested it is of the sort in my attachment, starred to show how common this practice is. So yet again I ask for the full question. @popcornfrenzy If you are not confident with these, there are many books of nothing but practice (drill) questions with answers. Practice makes perfect
  2. From what you have said before, I would think the final objective might be to help you understand the following presentation about dilution and pH calculation in swimming pools. https://courses.lumenlearning.com/cheminter/chapter/calculating-ph-of-salt-solutions/
  3. It looks to me like the sort of 'question' you find in texts on Pharmacy or Pharmaceutical calculations. Very often there is a general question such as "For each of the following mixtures of 100 mL of each, calculate the number of milligrams of each ion present in the solution mixture" This is followed by a list of drill questions with different solutions. By itself it is incomplete. 'pf' or percentage fraction is generally used by Pharmacists to mean grammes per litre or g/L and should be writen 0.4% which means it contains 4 grammes per litre of solution. For
  4. This is not a question Nor is it a complete statement. So first you need to get is a full and accurate statement of the question and the values of the concentrations concerned.
  5. Different parts of the body operate at different pH values. Some also operate a variable pH values for instance there are literally thousands of catalysed body processes many of which are pH sensitive. So the first question is What do you mean by the body pH ? The body processes alkaline foods in the stomach with stomach acids and further in in the digestive system it processes alkaline foods. This I understand is the basis of the 'Hay Diet' The little experience of this I have seen in others, is that dieting works by reducing calorie intake eg substituting cabba
  6. A solution is a mixture of two or more substances. Just to consider two, A and B - alcohol and water or salt and water. The mixture contains a certain % of A and (100 - %A) of B Adding (pure) A or B to the mixture will increase the concentration of A or B, decreasing or diluting the concentration of the other. In other words diluting is the opposite of concentrating. I know in common parlance we often use diluting to mean to add water. This is not untrue just only part of the full (scientific) story.
  7. Do try to do the short question I asked at the end about common salt. It is meant to help develop your understanding.
  8. Science in general does not do 'proofs' - That is for Mathematicians and Lawyers, although their definitions of the word are somewhat different. Science does hypotheses and deductions, which can tested against observations. But it should always be open to modification following further observations which show something different.
  9. It doesn't change anything, it is not a proof. It is a derivation to show where it comes from. It also shows that you are correct a little bit of information is lost in the derivation process and it is a matter of convention which way up we define the fraction. This is an arbitrary choice that is internationally adopted and must be simple remembered. I think I made the comment that remembering which way up trips many students up so stressed this point. The convention adopted does has the advantage that these constants are very small (much less than 1). So this mak
  10. Actually I have come across something connected to agebraic geometry and group theory. I have just been trying to remember it. But not to vectors. You require a whole lot of extra mathematical structure for vectors. I certainly think that is the wrong tree to bark up. Look at it like this 15 = 5 x 3 ie it factorises into 5 and 3. But 15, 5 and 3 are all numbers (integers to boot). That is they are all the same kind of (mathematical) object from the same set. This is a consequence of and consistent with the axiom of multiplication that for every
  11. Some of them are indeed oversimplifications. They are not always valid and do not necessarily lead to a conservation law. However since you refuse to answer my question here are the words of your guru on the subject I asked you about. So have you ever met the half-side of a cube ? Of course one half-side times another half-side (of a cube) gives you the area of a quarter side Whereas A whole side times a whole side gives the area of a whole side. Much more pleasing, yes ? Is there something wrong with discussing radii and diameters ?
  12. Sorry I wasn't completely clear. The thing is that 'Millikan's Experiment' was not one single experiment at all. It was a determined effort by Millikan to measure several important properties of 'the electron' over several experiments during the years from 1909 to 1913. The results and conclusions of this work were first published Phil. Mag., 34, p1, 1917 and later in a series of books which started out with the title The Electron and was revised a couple of times to The electron: its isolation and measurement and the determination of some of its properties. (1919) and later e
  13. Instead of being rude and condescending about our abilities why not just post the requested information and see if we understand it ? I note you have ignored my comment about diameters v radii. Using diameters instead of radii is equivalent to asking "what is the diameter of curvature in differential geomery ?"
  14. It's a very good and perceptive question. +1 It should be noted that the original experiment as conducted by Millikan was very different from the simplified one studied in schools and actually carried out in some of them. In particular neither Millikan nor anybody else originally knew what the charge was. The droplets from the atomiser were ionized by means of X rays. Since then it has been discovered that friction within the atomiser is sufficient to ionise the droplets and that they then carry a negative charge. Also it was not originally known that there was a unit
  15. This leads to put y = 2 then x2 -2x +1 =0 (x-1) (x-1) = 0 x =1.
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