Melting Point Lab

The small sample fell apart after the roasting process, making it hard to separate from the charcoal. Also, I think allowing more time to let all the copper(II) oxide be smelted would have increased the accuracy of our results.

In part 2 of lab 4, we had a similar process with some difference in solutes. We obtained 2.0 grams of impure benzil and mixed it with 10 ml of Ethanol. The exact same process in part 1 was repeated in part 2. However, our aim in part 2 was to see a clear liquid with black powder floating, unlike that of part 1. An additional difference was that we saved our crystals in part 2 for further experimentation at a later time.

The materials that were used to carry out the experiments on the water samples were ten testing kits. We ran 10 tests on all

Results: For part one of Lab 3a, Day one, the beginning unknown mineral was a blue-green color. The mineral was charcoal colored after the roasting process. Roasting caused the mineral to lose mass. The lost mass was due to release of gas.

Turned back to dark blue liquid, within a few minutes turned to solid and fuchsia

Before heat the water was in the compound which made the crystals appear to be bigger rather then why it became an anhydrous when the heat was added and the water was removed which made the crystals appear smaller. Because the crystal changed from and colour this proves that there was water that has been removed to make this change. Error Analysis Some sources of error may have been that the water was not fully gone, and that the beaker may have still been hot when the mass was measured.

A solute and solvent were chosen from the list to start with. Around 10 mg of solid and 0.25 mL of solvent were added to a clean reaction tube. A pipette was useful in transferring the solvent to the tube. The mixture was stirred with a glass stirring rod. If the substance was completely dissolved at room temperature, a few drops of water would then be added to see if the solid precipitated.

CHE 133 Experiment 3, General Chemistry II Lab, Spring Quarter 2014-2015, DePaul University. [Online] https://www.d2l.depaul.edu (accessed April 25, 2015)

We then will use the equation mass / volume and get the density. Now for the second section of the experiment to find the boiling point of a liquid we are going to need a thermometer, beaker , test tube , heat source we will boil the liquid and get the boiling point of it by using the equation ( t1 + t2)/2. To get the melting point of a solid we are going to need a mel-temp, bunsen burner , thermometer, and a capillary tube. We should not need any equations because once the liquid form of the solid starts to melt we will record that temperature +/-

the purpose of this lab was to find heat capacity and to calculate the specific heat.

Freezing is when a liquid turns into a solid. Melting is when a solid goes to a liquid. Evaporation is when liquid turns to gas. Sublimation is when a solid turns to a gas. Lastly, deposition is when a gas turns into a solid. A third way to classify matter is to tell if it is a pure substance or if it is a mixture. A pure substance has two types, whether it is an element or a compound. An element is just one single atom while a compound is two or more atoms, that create a molecule and are the same, bonded. A mixture is a mix of atoms and/or molecules, and/or pure substances. So for example, let's say you have oranges and apples in a bowl, that is considered a mix because they are not physically bonded together and they are not the same. This goes the same for a mixture, but on a molecular level. Mixtures are also determined if they are homogeneous or

The purpose of this experiment is to identify an unknown substance by measuring the density and boiling point. I will be able to conclude which substance is my own from a list of known options stating what its real boiling point and density is.

The purpose of this lab was to determine the molecular mass of a compound by measuring the freezing point depression. Freezing point depression is one concept discussed within this experiment, additionally, in class too. Freezing point depression is a colligative property, which refers to one that depends on the number of particles in a given volume of solvent, rather than on the chemical nature of the particles. Another concept applied to this experiment is the cooling curves, which for a pure solution does not plateau when the phase change occur, rather the rate at which the temperature decreases becomes slower. The cooling curve for the pure solvent, on the other hand, has a plateau because there is no solute within it that affects the temperature.

When looking at all three plots, the trend for all three properties is to increase as carbon number increases. This supports the information available about melting and boiling point. The melting point and boiling point are the temperatures at which the molecules have enough energy to overcome the intermolecular forces holding them together4. Melting point is the temperature at which a group of molecules changes from solid to liquid, and boiling point is the temperature at which a group of molecules changes from liquid to gas. Enthalpy of vaporization is the heat that is required for a substance to go change from a liquid to a gas.5 Melting point, boiling point, and enthalpy of vaporization all involve a required temperature or energy for a

Farrell, R. M., Metcalfe, J. S., McGowan, M. L., Weise, K. L., Agatisa, P. K., & Berg, J.