Which of the following reactions show a decrease in entropy?

Question

anonymous · Answer

CaO(s) + H2O(l)  Ca(OH)2 (s) 
 2H2O (l)  2 H2 (g) + O2 (g) 
 H2CO3 (aq)  CO2 (g) + H2O (l) 
 2KClO3 (s)  3O2 (g) + 2KCl (s)

aaronq · Answer

decrease in entropy

                 (g) ->(l) ->(s)
more molecules -> less molecules

anonymous · Answer

so would it be C

aaronq · Answer

no, the reaction goes from liquid to gaseous and solid, the (l) -> (g) shows an increase in entropy

anonymous · Answer

B? because it goes from liquid to a gas >?

aaronq · Answer

liquid to a gas is AN increase in entropy because you're increasing the disorder of the system. you're looking for a decrease

anonymous · Answer

oh ok so you wanna go backwards so its C

anonymous · Answer

you go from a gas to a liquid...

aaronq · Answer

H2CO3 (aq) ->  CO2 (g) + H2O (l) 

is that going from a gas to a liquid?

anonymous · Answer

no i guess its going from an aqueous solution to a gas and liquid? so is it right or no

aaronq · Answer

it's not correct, you're increasing the entropy by going from a liquid to a gas

anonymous · Answer

i think its D

aaronq · Answer

why do you think it's D?

anonymous · Answer

cause it has a liquid then goes to solid

dls · Answer

@aaronq is it A?

anonymous · Answer

opps im looking at A

aaronq · Answer

yep it's A

dls · Answer

CaO(s) + H2O(l)  Ca(OH)2 (s) 
liquid=>solid

anonymous · Answer

thanks guys

anonymous · Answer

@DLS  @aaronq

aaronq · Answer

no problem dude

dls · Answer

yw :)