Which salt will add the least warmth to melt an ice cube?
Gözde Kaçmaz & Habibe Özcan
Pieter Nieuwland College, The Netherlands
June 2011
Summary
Our research question is: which salt will add the least warmth to melt an ice cube?
To answer the research question we have used the following solutions of: sodium chloride
(NaCl), mono soda carbonate (Na2CO3∙H2O), ammonium chloride (NH4Cl) and sand (SiO2). We
have chosen for these materials because all four are used to melt ice.
We conducted the survey as following: first weight 10 grams (10 gram coated the surface.) of
salt in a measuring cup filled with 100 grams of water(100 gram, because it’s a easy number to
calculate with)Then we measured the temperature of the solution with and without the ice cube.
With those results and data we could calculate the heat by using the formula: Q = c * m * dT.
Introduction
The aim of our study is to find out the
amount of heat you will need to melt an ice
cube. In this research we used the following
salts: sodium chloride (NaCl), mono soda
carbonate (Na2CO3∙H2O), ammonium
chloride (NH4Cl) and sand (SiO2).
Our hypothesis is that we have to add less
NaCl because NaCl ensures that the melting
of ice will decrease. NaCl on the ice cube
provides pickle. And pickle provides for a
lower melting point, which means the ice
cube will melt faster.
Preparation
To conduct our research we have used the
following materials:
• 20 grams soda chloride
• 20 grams soda carbonate
• 20 grams ammonium chloride
• 20 grams sand
• Thermometer
• Measuring cups
• 10 ice cubes
We have used 20 grams of each substance,
because we carried out the survey twice. We
added 10 grams of every salt because 10
grams coated the surface.
Procedure
First of all we weighed 100 grams water and
10 grams of each salt. Then we put those
two together as one solution. We measured
the temperature of the ice cub until it had a
temperature of 0 degrees Celsius( so that
the temperature of the ice would not affect
our study) We have done it the following
way: we placed the ice cube into a
measuring glass and then we kept the
thermometer against the ice cube. After that
we putted the ice cube in the water with salt
and waited until it had melted. We also
measured the temperature of the water
before and after the ice has melted.
Results
To calculate the heat that has been added
from the endothermic reaction we used the
following formula: Q = c * m * dT.
Q: the heat, what was added during the
endothermic reaction (kJ/kg x 10^3)
c: the specific heat of the solutions (J / kg /
K). We have read out the specific heat from
tables and graphs (see bibliography for
which they are)
m: the mass in the formula is the mass of the
solution (kg)
dT: the temperature difference between the
temperature of the water before and after
the ice cubes had been molten. The results
in the following table are in Kelvin:
Solution
H2O
NaCl
Na2CO3
NH4Cl
SiO2
First measurement
T start
293,2
290,2
290,2
289,2
293,2
Solution Specific heat
(J/kg/K)103)
H2O
4,18
NaCl
4,15
Na2CO3 4,03
NH4Cl
4,52
SiO2
5,01
Mass
( kg)
0,10
0,11
0,11
0,11
0,11
Second measurement
T end
286,2
284,2
285,2
284,2
287,2
Average
dT (K)
8,5
5,5
4,5
4,5
6
dT
7K
6K
5K
5K
6K
T start
294,2
293,2
288,2
291,2
291,2
Calculation of
the heat
4,18*0,10*8,5
4,15*0,11*5,5
4,03*0,11*4,5
4,52*0,11*4,5
5,01*0,11*6
T end
284,2
288,2
284,2
287,2
285,2
Average dT
dT
10 K
5K
4K
4K
6K
8,5
5,5
4,5
4,5
6
Q
( kJ/kg)103
3,56
2,51
1,99
2,23
3,31
Conclusion
From our results we conclude the following:
you must add the least energy to soda ash. The
energy in the form of heat was 1,99 kJ x 10^3.
Which was not in settlement with our
hypothesis.
Evaluation
As with any experiment, we also had to deal
with measurement uncertainties. For
example, we could use some better
equipment to measure data. Especially for
the reading of the temperature. This was
very important because a thermometer is
not that precise. What went well afterwards,
was that we conducted all the experiments
twice just to reduce the measurement
uncertainty. A suggestion for the next time
is to exclude to use demineralized water or
tap water, which mostly could have had an
influence on the reaction. You can use
distilled water because it is made differently
than tap water, and perhaps will it have a
different effect than tap water. And whether
the combination of salts can provide a better
solution. We can reduce the amount of salt,
because salt that is sprinkled in the winter
never quite cover the surface of the road.
Finally, we don’t know how reliable our data
from the Internet is.
Bibliography
 http://en.wikipedia.org/wiki/Nacl
 http://en.wikipedia.org/wiki/Salmiak
 http://en.wikipedia.org/wiki/Sio2
 http://en.wikipedia.org/wiki/Na2co3
 Binas
 http://www.genchem.com/pdf/SodaA
shTech.pdf
 http://www.engineeringtoolbox.com/
water-thermal-propertiesd_162.html
 http://www.endmemo.com/convert/s
pecific%20heat%20capacity.php
 http://www.jiskha.com/