S. heat capacity and other things (1 Viewer)

[Aerlinn]

A 0.254g sample of black coal was burnt in a bomb calorimeter. The calorimeter contained 300ml of water which rose from 19.25C to 24.92C
a) Using the specific hat capacity of water, calculate the heat of combustion of the coal ... which i've done
b) Is your answer likely to be higher or lower than the actual value?
Huh?
The casing of a dry cell that is left operating in an appliance for several weeks can begin to disintegrate, causing damage to the appliance. Explain why this occurs.

When constructing a galvanic cell in the laboratory, two separate containers are generally used for the half cells. However, in commercial cells, such as the dry cell, all the reactants are palced in the one container. How are commercial cells constructed so that the use of two containers is avoided?

Hoping someone can offer some insight in any of these :wave:

 

[xiao1985]

1b lower... energy loss. though bomb is alot more accurate than a foam cup, it is still prone to energy loss.

2 dry cell = oxidizing zinc casing on the out side... over usage = zinc casing all erode away. the electrolite (liquidy ugly stuff) will flow out and kill the electronics

3 Using insulators to prevent short circuiting?!

 

[Aerlinn]

1b. ah, ok. All calorimeters are prone to energy loss yes?

2. Interesting the way you've described it xD
3. I have no idea either... (although not sure I understand...

Using insulators to prevent short circuiting

)

 

[xiao1985]

3) either they have 2 beakers, one inside an other (so seemingly only 1)

or they use solids to prevent liquid from mixing.