°°The next Lunar Eclipse is on March 23, a Wednesday THIS YEAR - 65 days left!
°° A Lunar Eclipse happens when the moon passes directly behind the earth into its umbra, or, shadow. This can occur only when the sun, Earth and moon are aligned exactly, or very closely so, with the Earth in the middle. Hence, a Lunar Eclipse can occur only the night of a full moon. The type and length of an eclipse depends upon the Moon's location relative to its orbital nodes. Isn't that cool?
↑ ↑ ↑ Hope this helps! :D
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1. Remember (sum of products) - (sum of reactants)
So ΔHrxn = 2 ΔHf [H2(g)] + ΔHf [Ca(OH)2(s)] - 2 ΔHf [H2O(l)] - ΔHf [Ca(s)]
= 2*0 + -986.09 kJ/mol - 2*(-285.8 kJ/mol) - 0
Do the math and you'll have the answer. BTW the ΔHf [H2(g)] and ΔHf
[Ca(s)] were 0 because these are elements in their standard states.
</span>HOPE THIS HELPS ;)
