Lab Assignment heat of fusion/vaporization

Apr 2013
7
0
Hi. I need help with a lab assignment. The assignment consisted of measuring the temperature change of ice to demonstrate phase changes. But the directions for calculating enthalpy don't make any sense at all.

According to the lab assignment, to obtain the heat of fusion, I must divide

time to melt/moles of ice

This is supposed to give me the enthalpy of fusion, but it doesn't give the enthalpy of fusion or a number even close to it. Has anyone done a lab like this and could you help me make sense of the directions which are unclear?
 

Unknown008

CHF Hall of Fame
May 2010
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Mauritius
That's a strange experiment... there's no time related to the heat of fusion. The formula that gives the heat of fusion is:

Q = mL

Where Q is the quantity of heat, m is the mass and L is the specific latent heat (for melting, it is the specific latent heat of fusion).

So, L = m/Q

I would rather expect something like:

1. Take mass of water.
2. Take mass of ice cube.
3. Record initial temperatures.
4. Put ice in water.
5. Record final temperature of water as soon as all ice melted.
6. Q will then be obtained from Q = mcT for water (m is total mass of water, c is specific heat capacity of water, T is Tf-Ti (Final temp. - initial temp).
7. The use L = Q/m, you get Q from step 6 and m is mass of ice cube.