# Thermodynamics and Coffee Cup Holder

Topics: Thermodynamics, Chemistry, Temperature Pages: 2 (334 words) Published: November 1, 2012
Discussion
2mol of HCL * V = 50 cm3 * 1 mol
50/2=V
V=25 cm3
Volume needed to neutralise 50 cm3 of 1 mol dm-3 of NaOH is 25 cm3 of HCL b)
Independent variable: Volume of HCL
Dependent variable: Temperature of mixed solution
Controlled variables: Volume of alkaline, Concentration of acid, Concentration of alkaline c) Burette
d)Fix the burette into a burette holder securely. Pour HCL into the burette with a funnel until it reaches the 0.0cm3 mark.

e)The risk of using plastic cup in this experiment is that the plastic material is too thin which will cause the outside surface of the plastic cup to be hot due to conduction. Furthermore, plastic is not a good insulator as compared to polystyrene cup and this will cause heat loss which will affect the reading of the experiment ii)NaOH is a strong alkaline solution that can cause severe chemical burns if it is in contact with skin f)i) Since the paper coffee cup gets so hot, many coffee shops provide a thin cardboard holder so that you won't burn your fingers when holding the cup.

Coffee cup holder prevents burned fingers
The holder is corrugated, such that are there air gaps and only the ridges touch the cup.

Coffee cup holder has ridges inside
The air gaps mean the heat transfer must be done by convection, which is less effective than conduction. With only the ridges of the holder touching the hot cup, much less heat transfer by conduction occurs.

ii)Wear full lab equipment such as lab coat,googles,and gloves to reduce exposure of skin.

G) total heat energy produce in plastic cup =R
R =Total volume of mixture (HCL+NaOH)* 4.18 *∆T
R=75g *4.18 *∆T
h)The R value is divided by 1000 to convert the value into kJ.The newly divided value is then divided by the number of moles of H2O and the value obtain ∆Neutralisation (kJ mol-1)