15539/2.9 = 5358.27 calories.
The energy used was 5352.27 calories.
Discussion.
The graph shows an increase in temperature up to a certain point (106°C), which is just above the boiling point. After this the temperature flattened out, and became stable on 105.5°C, despite the fact that the same amount of heat were given out by the flame after the water had reached its boiling point. The reason why this happen can be explained with what happens with the water molecules. When the water reach boiling point, the hydrogen bonds break, and the liquid is turned into steam. This makes the temperature stabilise itself after reaching boiling point. This can also be observed in human beings. When the body heats up it will start to secrete sweat through the different sweat glands of the body. This causes the body temperature to become stable. .
Water has a high energy capacity because it takes a lot of energy to break the bonds of the H2O molecules. It is important for the homeostasis that humans have a lot of water in the body. The water helps keeping the body temperature stable, because it takes a lot of energy to change the temperature.
Experiment Two.
The aim of this experiment is to try to melt the sodium chloride, and see if it has a strong or weak bonding.
Method.
Please see handout for this experiment.
Results.
After heating up the sodium chloride (NaCl) for 5 minutes and discovered that nothing happened to it.
Discussion.
Sodium chloride contains two charged particles, Na+ and Cl-. Cl- is missing one electron to get 8 electrons in its outer shell, and Na+ has one electron too much to reach its goals of 8 electrons. This creates an electrostatic attraction between the two particles, and Na+ gets an electron from Cl-. These ions will stay together by the electrostatic attraction because they are oppositely charged. This is called an ionic bonding, and in this case it is called NaCl.
2Na++Cl- Ã 2NaCl.
Even five minutes of heating could not break the bonds.
