The reason fractions need a common denominator before adding or subtracting is so that the numbers of pieces you are adding/subtracting are all the same size. Note that the numerator of a fraction just tells you how many pieces you have of that size.
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Because the kind of compounfds that you try to determine using paper chromatography (organic compounds) are usually not soluble in water. Furthermore, water could react chemically with some of this compounds, because it's a very reactive molecule. You need organic solvents that are mostly inert.
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2
Step-by-step explanation:
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Correct statements:
Step-by-step explanation:
A line that rises from left to right has a positive slope.
A line that falls from right to left has a negative slope.
A horizontal line has no slope. (slope of 0)
I cant help you on this if there is no coefficients.
