To investigate how the temperature of water affects how salt dissolves. Prediction - If the temperature is warmer, the more solute will dissolve in the solude. Variables - which variables are you going to:
Independent Variable - The temperature of the water.
Dependent variable - How much salt is needed to not dissolve in water.
Controlled variables - The materials.
How will you make it a fair test? - Using a machine to weight the salt and heat the water.
What impact would it cause if those Independent Variables were changed? - How much of the salt dissolves.
Materials -
250 mL Beaker
[1] Scale
40g of Sodium chloride
[1] Spoon
[1] Mixing stick
[1] Hot plate
100 mL of water
[1] Thermometer
[1] …show more content…
The water was measured by eye, having the beaker held at eye level to get the most accurate answer.
Then, the watch glass was put on the scale and teared to reset the weight shown on the screen.
Next, the desired amount of sodium chloride ( salt) was placed onto the watch glass. In this case 5g of sat at room temperature was placed.
The salt was then poured into the beaker and stirred using the mixing stick until it was dissolved to the point where it couldn’t been seen by the naked eye.
Steps 3 and 4 were repeated until the salt no longer dissolved into the solution.
While an assistant or partner was stirring the solution, the hot plate was turned on and the dial turned to ‘high’ so that it heated faster. Once the solution could no longer be dissolved, the beaker was placed on the hot play to heat.
Next the thermometer was used to keep track of the temperature of the water and the dial on the hot plate was adjusted to keep a constant temperature. The first temperature was room temperature, then 40 degrees, then 60 and finally 80
Steps 3 and 4 were repeated until the salt couldn’t dissolve, then the heat was raised to the next …show more content…
The pattern is, when the salt stops dissolves, heat the water. This obviously will only work to some extent.
This happens because the heated water also heats the salt and as it is heated, it comes closer to melting point, making it less dense. The warmth causes the salt particles to vibrate more and the atoms move apart slowly, causing the salt to melt until it dissolves into the water.
The difficulty in this experiment was heating the water. Using the hot plate took a long time to heat up and once it did, it didn’t cool down. This mean that when the beaker was placed on the plate, it heated past the temperature wanted. This happened because the hot plate was left to heat up for too long. It should have been turned off or down when it was halfway to the heat wanted so that when it finally stopped getting hotter, it was the right temperature.
Having a machine control the heat plate so that there is a constant temperature would be better because the salt would be affected equally.
Conclusion