Transcript Solubility Lab

Solubility Lab
This presentation will show you how the Solubility Lab could have been
written up correctly. Please make corrections on your own lab.
Purpose:
The purpose is to see if temperature
affects the rate of solubility.
Variable:
Different temperatures of water (hot,
room temperature, and cold)
Dependent Variable
 Thing = RATE (TIME)
 Unit = SECONDS
 Tool = STOPWATCH
 Some of you said that the thing was TEMPERATURE. Did you take the time to
think about that? Think about how that would change the purpose. You would
then be saying…..The purpose is to see if temperature affects temperature.
 Does that make sense?
No!!!
Hypothesis:
If a drop of food coloring is added to water
of different temperatures, then it will
become a solution fastest in the hot water.
Data Chart:
Water
Temperature
Time
Cold
Room
Temperature
40 degrees C
300 + seconds
60 degrees C
230 seconds
Hot
85 degrees C
53 seconds
Written Observations
Cold Water – When the food coloring was added to
the cold water, it very slowly moved down towards
the bottom of the beaker. Very little of the food
coloring was spreading out around the beaker. After
300 seconds, the majority of the food coloring was
mixed with only the water at the bottom of the
beaker, and almost all of the water above it was still
clear.
Written Observations
Room Temperature Water – When the food
coloring was added to the room temperature
water it still moved towards the bottom, but this
time it was swirling down and a bit more of the
top portion of the water was colored. Little by
little, the food coloring moved upwards and
around the sides of the beaker. At 230 seconds,
the water was a solid color.
Written Observations
Hot Water – As soon as the food coloring hit the
hot water it started moving around in all
directions. Every place the food coloring went it
turned the water to that color. The color of the
water on the bottom of the beaker was the same
as the color of the water on top. In only 53
seconds the water was a solid color.
Conclusion – Parts 1-3
The hypothesis was supported by the data and observations.
The temperature of water does affect the rate of solubility. The
warmer the solvent is, the faster it will become a solution with a
solute.
During the experiment there was much more movement in the
beaker with hot water than there was in the other two temperatures.
The warmer the water was, the faster the food coloring was moving,
and the cooler the water was, the slower it was moving. The solution
formed in the hot water in only 53 seconds, while it formed in 230
seconds in the room temperature water. The food coloring in the cold
water did not become a solution during the time it was observed,
even after 300 seconds.
Conclusion – Part 4
A solute is a substance that is dissolved into another substance. In a solution there
is usually less of it. A solvent is the substance, usually a liquid, that is doing the dissolving.
A solution is a homogenous (even) mixture of a solute and solvent.
In the solubility lab, the solute was food coloring, the solvent was water, and the
solution was colored water.
A solution of food coloring and water could still be made without heating the
water by stirring it. It could still be made without stirring it. It would just take longer.
Temperature can affect the rate of solubility in the same way that temperature
affected the rate of the chemical reaction during the Alka-Seltzer lab. In both
experiments, it was the behavior of the molecules inside the water that caused the
different rates (times). Since molecules move faster in warmer liquids there are more
collisions (crashes) between molecules. Those collisions helped break down the AlkaSeltzer faster. Cooler water causes molecules to move slower, causing less collisions and a
longer reaction rate for the Alka-Seltzer to break down. In the Solubility Lab, the faster
moving molecules in warmer water literally moved the food coloring along with them,
acting very much like a spoon stirring the water. The cooler the water was, there was less
movement of the molecules and less “stirring” of the solute and solvent, causing a longer
time for them to become a solution.
Conclusion – Part 5
Oil and vinegar salad dressing is not a solution. A solution
is defined as a homogenous (even) mixture between two or
more things. Since the oil and vinegar do not distribute evenly,
it is not considered a solution. Shaking the bottle will only
temporarily mix the two liquids, and they immediately begin to
separate.
Even if the temperature of oil and vinegar were increased
they still will not become a solution. They still will not mix.
The scientific term that describes a mixture of oil and
vinegar is an emulsion.