The best answer is A) <span>It shows how the temperature of the substance falls as heat is removed.
The cooling curve shows how the temperature of a substances changes with time, as it is allowed to cool. The substance is first heated until completely liquefied, and then allowed to cool. The flat parts of the curve, where temperature is constant with time, show the periods in which the state of matter of the substance changes. One the substance completely changes it state of matter, namely changes from liquid to solid, its temperature continues to drop.
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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 ;)
Quantity of K2S m = 0.105 m
Number of ions i = 2(K) + 1(S) = 3
Freezing point depression constant of water Kf = 1.86
delta T = i x m x Kf = 3 x 0.105 x 1.86 = 0.586
Freezing point = 0 - 0.586 = 0.586 C
Boiling point constant of water Kb = 0.512
delta T = i x m x Kb = 3 x 0.105 x 0.512 = 0.161
Boiling point = 100 + 0.161 = 100.161 C
Answer:
Gases can be compressed easily because there is a large amount of space between the individual molecules, which are very active and move around at high speed.
Explanation:
When gas is compressed, the particles are forced much closer together, allowing a huge amount of particles to fit in a small space.