Answer: Correct option is B)
The standard enthalpy change of formation of a compound is the enthalpy change which occurs when one mole of the compound is formed from its elements under standard conditions. The equation showing the standard enthalpy change of formation of water is
H
2
(g)+
2
1
O
2
(g)⟶H
2 ↑
O(l) 1 mole of water formed.
∴ Enthalpy of formation is −X2kJ/mol.
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Explanation:I hope this helped
If I could change something in my previous science classes, it would have been the fact that I struggled in the question concerning exponents. It was simple one, but I don't know how I didn't understood that. For example, if there is a question with a calculation "xy²", then I would first multiply x and y, and then calculate the exponent. I did 3 of the questions wrong because of this, it was when I was in 7th grade. I wish I had not done this kind of silly mistake. I an in 10th grade and understand it well now, though.
speed = distance / time
v = d / t
If we simplify this and isolate t, then we get t = d / v
Scientists use models to study atoms because so they can prove that their experiment(s) are right/make sense. :)
