Chemistry Question.

[Yoyo1994]

Hello all, I've got a doubt that comes from October/November 2010. It is question 17, which states:

When pink crystals of cobalt(II) chloride are heated, steam is given off and the colour of the solid changes to blue.
CoCl2.6H2O (reversible reaction sign) CoCl2 + 6H2O
What happens when water is added to the blue solid?

Colour ---------- Temperature
A changes to pink ---------- decreases
B changes to pink ---------- increases
C remains blue ---------- decreases
D remains blue ---------- increases

I chose A but it seems the answer is B. I thought that it was A because when in the beginning heat was absorbed into the crystals it was endothermic and heat is increased in the crystals and decreased in the surroundings. When water is added the whole thing is reversed and it is exothermic where heat is lost to the surroundings by the crystals and the temperature in the crystals decreases and increases in the surroundings.
Now, if I thought they were referring to the surroundings I would have chosen B but they clearly asked about what happens in the crystals when they used "colour" and "temperature".
Can someone explain to me why I got this wrong? Thanks.

 

[brainiac]

well in my opinion ....... i think it is B because no energy is supplied now to the product .. and when the water is added ,with the colour change the temprature would also increase as heat would be released to the surroundings . i hope u understood

 

[JmCullen]

it's B..
since it's reversible reaction.
so if pink to blue, it will change back from blue to pink.
and if temperature increase, backward reaction is favour.
so it's change to pink and increase in temperature

 

[Yoyo1994]

Increase in temperature in the crystals or the surroundings?
They ask for the crystals I think, and an increase in the surroundings is correct, but when they ask for the crystals it should be a decrease of temperature in the crystals which cause an increase in the surroundings. Is that correct or do I misinterpret what is going on?

 

[JmCullen]

i think what it means of increase in temperature is, when u heated it with a higher temperature.

 

[Yoyo1994]

i think what it means of increase in temperature is, when u heated it with a higher temperature.

I'm not sure about that :S