6.03 Calorimetry Lab

Besides the inaccuracy in determining the freezing point and problems in the enthalpy of dissolution, the largest source of error was the temperature probe. Over the course of the multiple trials, the temperature probe would read somewhat inconsistent values. Due to this uncertainty, trials were performed on pure deionized water to see how far the probe read from zero degrees Celsius. Another source of error was in the calorimeter. Using two foam cups as a calorimeter is sufficient, although far from perfect. Using a bomb calorimeter would be much more accurate. Even calculating the calorimeter constant through experiment and taking this into account, this was still a large source of error.

Procedure: first we found the mass of the empty graduated cylinder and then its mass with the now distilled unknown. After subtracting the mass of the graduated cylinder, we were able to find the volume. For every 1mL=1cm³ so there we had the volume found with the graduated cylinder. We divided the mass by the volume in order to get the density

In the first part of the experiment, Part A, the standard solutions were prepared. As a whole, the experiment was conducted by four people, however, for Part A, the group was split in two to prepare the two different solutions. Calibrations curves were created for the standard solutions of both Red 40 and Blue 1. Each solution was treated with a serial 2-fold dilution to gain different concentrations of each solution.

Based on the obtained results from the experiment, the unknown liquid was determined to be methanol. The results were very close to the theoretical values, all within 15.92 % error. In this experiment it showed that the methanol have different intermolecular forces at work and at different vapor pressures implying that the amount of intermolecular forces they exhibit affects the vapor pressure. Possible source of error that occurred throughout the experiment was that the temperature was hard to control leading to the variances between the temperature of the reading in the water bath and the actual temperature causing slight changes in the vapor

The topic of research is, “how fast does an Alka-Seltzer tablet make gas?”. In the experiment, the scientists will be measuring the chemical reaction rates that occur, when 1 Alka-Seltzer tablet is placed in a specific temperature of water. The independent variable during the experiment will be the temperature of the water (degrees Celsius). The dependent variable during the experiment will be, the rate in which gas is produced (in seconds). The constants of the experiment, will be the amount of water used and the Alka Selter compound. The control in the experiment is water. Units used while timing the productivity of gas from an Alka-Seltzer tablet in different temperatures is, seconds.

The Gummy Bear experiment illustrates osmosis, a type of diffusion involving the movement of water molecules through a semi-permeable membrane. The gummy bear represents the semi-permeable membrane. The area inside of the gummy bear had a higher solute concentration than the area outside of the gummy bear, so the water was moving. In situations like this, water tries to move from an area of high water concentration (or low solute concentration) to an area of low water concentration (or high solute concentration). The water moves around until it achieves an equilibrium. In the Gummy Bear experiment, two gummy bears of the same color were first massed and measured. Then, 150 milliliters of water was placed in a cup along with a gummy bear. Next,

To investigate and compare how different temperature (5℃, 15℃, 25℃, 35℃, 45℃) can affect the concentration of carbon dioxide in soda water through titration with sodium hydroxide solution.

Cell membranes are the semi-permeable membrane that surrounds all cells. It separates the extracellular environment from the intercellular environment. It is a phospholipid bilayer which contains various proteins, lipids and carbohydrates all serving different purposes. It is this structure which allows for the transport of nutrients, proteins and water. (Nature.com, 2014). Through extensive testing it has been found that small alcohols, specifically ethanol can increase the fluidity and membrane permeability of the phospholipid bilayer (Patra et al, 2005). The aim of the experiment was to test what effect that ethanol solution would have on the membrane

First, two grams on an unknown white compound were given. The possible compounds the known could be were CaCO3, KNO3, NH4Cl, CaCl2, K2SO4, (NH4)2SO2, Ca(NO3)2, NaC2H2O2, K2CO3, MgCl2, Na2CO3, 0.1 M AgNO3, MgSO4, NaCl, 0.2 M BaCl2, KCl, NaSO4, Mg(s), HCl, HNO3, NaOH, HC2H3O2, H2SO4, and KOH.

Rocks are intriguing to many individuals all over the world. Being made up of one or even many minerals, rocks draw an overwhelming amount of attention to themselves. When a probe brought back samples of rock from Planet X the task of identifying the rock was assigned. With no prior knowledge of the type of rock presented one will need figure out the identity of the rock based only on its density and physical properties. With an experimental process, one will begin to compare and uncover the identity of the rock samples brought back.

A number of different items were measured in this lab. For each of the following items, what did you find most challenging in making the measurement and how did that challenge affect the accuracy of the measurement?

5 water bath were set up each to10 °C. (5 were used do the experiment faster)

This experiment demonstrated water density because the cold water moved beneath the hot water, because it is denser.

In this experiment, the amount of water lost in the 0.99 gram sample of hydrated salt was 0.35 grams, meaning that 35.4% of the salt’s mass was water. The unknown salt’s percent water is closest to that of Copper (II) Sulfate Pentahydrate, or CuSO4 ⋅ 5H2O. The percent error from the accepted percent water in CuSO4 ⋅ 5H2O is 1.67%, since the calculated value came out to be 0.6 less than the accepted value of 36.0%.This lab may have had some issues or sources of error, including the possibility of insufficient heating, meaning that some water may not have evaporated, that the scale was uncalibrated, or that the evaporating dish was still hot while being measured. This would have resulted in convection currents pushing up on the plate and making it seem lighter by lifting it up

Two sources of error may have affected the experiment. Firstly, the experiment required volumes of liquid to be recorded while the vapours were distilling. It was impossible to accurately measure the volume of liquid at any given moment, as the meniscus was moving side to side. Secondly, the distillation was ended while there was still liquid in to round bottom flask. The composition and volume of this liquid were unaccounted for in the calculated