Chemistry- HWK CHECK
posted by Blair .
1. A solution in which no more solid can be dissoved is referred to as ____.
2.At constant pressure, heat can be referred to as (entropy, enthalpy, or free energy). Answer: enthalpy
The measure of disorder or randomness of a system is(entropy, enthalpy, or free energy). Answer: entropy
The spontaneity of a reaction is indicated by the direction of change of a system's(entropy, enthalpy, or free energy). Answer: free energy
3.The color of bromocresol green indicator is ______when pH < 4, green when pH 4- 5.3 and ______in pH > 5.3.
first blank =yellow 2nd blank= blue
4.Na2B4O7+ 10H2O(s) 2Na+ (aq) + B4O5(OH)42–(aq) + 8H2O(l)
The sign of (delta)Ssys will be
because there are..
moles of product generated.
5.The solubility of borax is directly proportional to temperature. Therefore, the sign of (delta)H is..
C. unknown with the given information.
#4 i put negative but i got it wrong
the answer to #4 should be POSITIVE & MORE ... the more moles produced, the greater the entropy, thus higher delta S
5 is c
5 is B
yea, #5 is fosho B
thanks a lot. i got #5 wrong. it's not B
The answer is B. 100%
5 is A
no 5 is c!
NO!!! ARE YOU RETARDED? ITS B!!!
wow... there are so many idiots on this sites because the answer is D!!!
okay forget what everyone else is saying. i just submitted my answer and B IS RIGHT. TRUST ME :)
i am not an iddiot
all of you who says B are just trying to screw everyone else's hw score over -__-
I didn't even bother reading the opinions about number 5 because they were too annoying, so I just thought about it myself and B, positive, is definitely the right choice because if borax is directly proportional to temperature, that means the more heat we add, the more the borax will dissolve in the water. When you add heat to a reaction, it makes the reaction endothermic and is therefore a positive delta H. If a reactions loses heat then it is a negative delta H. Oh and I just submitted it, and B positive is right.
(4 pts) The concentration and volume of reagents combined in each trial are listed in the table below:
Trial 00020 M 00020 M H2O(mL)
Fe(NO3)3 (mL) KSCN (mL)
1 5 2 3
2 5 3 2
3 5 4 1
4 5 5 0
Initially (right after combining and before any reaction occurs) the concentration of SCN– in trial 1 is
I put C for #5 and got it wrong it is not C
not so helpful peers lol
No u guys 5 really is B.. I wish i read these coments before putting C.. I regret it cuz C was seriouslyy wrong.. its positive. =D y would i try to screw everyone??? that's just mean.
5 is positive
5 is def. not c..i got it wrong
5 is positive! for me, positive was a. that's probably why some people got it wrong (:
5 is B. I really find it mean that people deliberately put the wrong answers on this site. Is the pursuit of a decimal's worth of increased standing in the class distribution really worth lessening your character? Why can't we just help each other out fairly?
#5: is Positive. It's not A, B, or C. Your question may be worded differently. But the correct answer should be "positive" for change in enthalpy. I did the lab, and my calculation supports it!
At constant pressure, heat can be referred to as (entropy) Read about entropy
The measure of disorder or randomness of a system is . (ethalpy) Definition of Entropy
The spontaneity of a reaction is indicated by the direction of change of a system's (free energy) Process of elimination if you want
Solid borax dissolves in water according to the equation:
Na2B4O7 10H2O(s) 2Na+ (aq) + B4O5(OH)42–(aq) + 8H2O(l)
The sign of Ssys will be If dS>0 then more molecules are produced. Look at the eqauation, 1 mole to start and 11 to finish. Go back to the definition of entropy about disorder.
because there are: Simple math 1 to 11 moles
The solubility of borax is directly proportional to temperature. Therefore, the sign of H is: We added heat so it is endothermic. Endothermic reactions are +. Exo is negative.
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Don't listen to majority of the comments. I am 100% correct.