Stark contrast to paths on energy surfaces or even mechanistic reactions, rule-based and inductive computational approaches to reaction prediction mostly consider only overall transformations. Overall transformations are general molecular graph rearrangements reflecting only the net change of several successive mechanistic reactions. For example, Figure 1 shows the overall transformation of an alkene interacting with hydrobromic acid to yield the alkyl bromide along with the two elementary reactions which compose the transformation.
Friction occurs when the surfaces and heat of two surfaces grind against each other.
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A voltmeter is the instrument used to measure a potential difference between two points in an electric circuit