There are a couple of ways todetermine if a reaction is exothermic or endothermic. Endothermic meaning that heat is added to the reaction to make the reactants interact and exothermic meaning heat is released during the reaction between the two reactants.
In endothermic reactions you can find a triangle above the arrow.
A) all mechanical waves need a medium to travel through.
This is true because mechanical waves move in a wave like manner at the atomic level. This is why an table vibrates when you put a speaker on top of it .
Answer:
C3H6
Explanation:
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I think D, not sure though!
U would subtract 90 minus 45 which equals 45
