Protons-19 because protons are equal to the atomic number which is 19 , electrons-19 electrons are equal to number of protons, neutrons-20 because the mass number of potassium is 39 so subtract 39 from 19 (atomic number) which gives us 20
Answer:
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Explanation:
the structural formula of butyl pentyl ether
<u>Answer:</u>
<em>A negative ∆H means that energy is given off from a reaction
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<u>Explanation:</u>

If the reaction has negative ∆H value then the reaction is exothermic

If the reaction has positive ∆H value then the reaction is endothermic
When Heat energy is given in the equation itself
If it is present on the left side it means that heat is absorbed and the reaction is Endothermic
If it is present on the right side it means heat is given off and the reaction is exothermic