Experiment : The Stock Solution

In six different 50mL volumetric flasks there was 0.00 mL, 2.00 mL, 4.00 mL, 6.00 mL, 8.00 mL, and 10.00mL of the 5.00 g/L Cu^(2+)stock solution. 3mL of 15M ammonia was added into each flask, once the ammonia was added each flask was diluted with water to 50 mL then were all thoroughly mixed.

Procedure: I used a ruler, thermometer, and scale to take measurements. I used a graduated cylinder, short step pipet, scale, and ruler to determine volume and density. I used a volumetric flask, graduated pipet, pipet bulb, scale, and glass beaker to determine concentrations and densities of various dilutions.

5. Experiment: Click Reset. Check that the Solute outside is 10 and the Initial cell volume is 40%. To calculate the solvent concentration, divide the number of solvent particles by the total number of particles, and then multiply by 100. (Note: The Gizmo only displays the solute concentrations.)

If the hypothesis is correct, the masses after we place the tubing samples in water will be higher than the masses before. We will see the greatest % increase in mass in the highest concentration of sucrose (1.0 M). The % increase will get lower as concentration decreases. All of the samples should have some increase in mass because we are placing them in distilled water. Based on the known solutions, the data should yield a mathematical model relating concentration and % increase, which we can use to find the concentration of the unknown solution.

The main focus of this lab was to measure different tonicities. Tonicity is the concentration of the solute particle mixed with the solvent inside the cell versus said the concentration of solute and solvent outside the cell (Mader 50). There are three different types of tonicity measurements. One type of tonicity is called isotonic. This means that the solution has an equal concentration of solute and solvent both outside and inside the cell (Mader 50). This means that the concentration is in an equilibrium. The second tonicity is called hypertonic. This type of solution has less free water outside of the cell and a higher concentration of the solute particle. Water exits the cell in order to balance the concentration inside and outside the

In the ADI Molarity Lab, the primary tasks was to use different values of moles of solute, volume of solvent, and molarity to find the mathematical relationships between them. To find these relationships, our group had to change the quantities of each of the variables and visually observe the molarity within the solution. For instance when using Cobalt (II) Nitrate to find the relationship between volume of the solution and the molarity of the solution; the group kept the amount of moles of the solute at a constant of 1.00 moles because if it would have changed it would have caused inaccurate data. We first set the volume of the solution to 0.2 liters. The molarity of the solution was 5.00 mol/L. Then we changed the volume of the solution

Time) because it had a correlation closest to 1. All three orders were graphed and a linear regression was used to see which graphed order was closest to 1. The order was determined by comparing the concentration and time to the mathematical predictions made using the integrated rate laws. Analyzing each graph and finding each correlation helped determine which graph was closest to 1. The more concentrated a solution is, the higher the absorbance of that solution. This is due to Beer’s Law. The law measures the absorbance of a solution by determining how much light passes through a solution. As the concentration of a solution increases, fewer wavelengths of light are able to pass through the concentrated solution. The absorbance at 60 seconds was 0.573 (Figure 1: Table1). To calculate the concentration (molarity), the Beer’s Law equation was used, Abs = slope(m)+b. Plugging in what is known into the Beer’s Law equation resulted in 0.573 = 3.172e+004 + 0, where the concentration is determined by M = 0.573-0/ 3.172e+004. So, the concentration at 60 seconds using the equation (M = 0.573-0 / 3.172e+004) was 1.824e-5 M. The 1st order graph resulted in k=0.006152 (Figure 1: Graph 1). Other groups also resulted in their decolorization of CV to be the 1st rate

The results showed the molarity of the NaOH solution. This experiment was completed twice and a new average molarity

One of the most important skills to have in the chemistry lab is the understanding of how chemicals will react. Knowing for example, how a chemical will react with a metal, is an excellent way of determining the amount of a particular metal in a deposit. This knowledge was used in this lab to determine the amount of copper in an unknown sample mixture. It is also known that the determination of the percent concentration of a certain solution, will directly effect the percent transmission and absorption of a solution, dependent upon its dilution. By first testing known concentrations of a solution, and plotting this information graphically, a line is formed

After the twenty minutes elapsed, the flask was cooled to room temperature and then titrated with the remaining NaOH until the colorless solution remained pink. The final volume was then recorded. While solution #1 was heating the same process was repeated with solution#2 and the second burette

The next step in this lab is to rinse the Erlenmeyer flask with distilled water down the drain and then repeat the experiment, this time adding 10 ml of 0.10M KI and 10 ml of distilled water to the flask instead. The flask should again be swirling to allow the solution to succumb to the same temperature as the water bath and once it has reached the same temperature, 10 ml of 3% H2O2 must then be added and a stopper must be immediately placed on the flask and recording should then begin for experiment two. After recording the times, the Erlenmeyer flask must then be rinsed again with distilled water down the drain. After rinsing the flask, the last part of the lab can now be performed. Experiment three is performed the same way, but instead, 20 ml of 0.10 ml M KI and 5 ml of distilled water will be added and after the swirling of the flask, 5 ml of 3% H2O2 will be added. After the times have been recorded, data collection should now be complete.

The major objective of the experiment was to test the effect of the concentration gradient on the diffusion rate. It was hypothesized that the greater the stronger the concentration gradient, the faster the rate of diffusion would be. To test this, dialysis tubes were submerged in different concentration fructose solutions. We weighed the tubes at specific time intervals to measure the rate of diffusion of water in each different solution. The results illustrated that increased concentration gradient increases the rate of diffusion of water in the tubes. We concluded that as concentration of the

Corresponding to the previous experiment, this week’s experiment measures the participants’ ability to conduct basic, fundamental laboratory procedures. These procedures revolve around scientific measurements of volume, mass, and density. Unlike last week’s activity, this week’s experiment had a few modifications. In addition to distilled water, saltwater and an unknown substance were added. There was a total of five substances to choose from; Hexane, Methanol, Ethyl acetate, Ethylene glycol, and Dichloromethane. Part C, the unknown liquid number was four, which the average density was 0.789 gmL-1, and from looking at the chart the unknown identity was methanol. Part A, the temperature of the water was 20 oC, which was in front of the class,

In this experiment, 0.31 g (2.87 mmol) of 2-methylphenol was suspended in a 10 mL Erlenmeyer flask along with 1 mL of water and a stir bar. The flask was clamped onto a hotplate/stirrer and turned on so that the stir bar would turn freely. Based on the amount of 2-methylphenol, 0.957 mL (0.00287 mmol) NaOH was calculated and collected in a syringe. The NaOH was then added to the 2-methylphenol solution and allowed to mix completely. In another 10 mL Erlenmeyer flask, 0.34 g (2.92 mmol) of sodium chloroacetate was calculated based on the amount of 2-methylphenol and placed into the flask along with 1 mL of water. The sodium chloroacetate solution was mixed until dissolved. The sodium chloroacetate solution was poured into the 2-methylphenol and NaOH solution after it was fully dissolved using a microscale funnel.

The volume of a small test tube and a thin-stemmed pipet were determined in this section of the lab. Water was poured into a small test tube until the water reached the very top edge of the test tube. The test tube was then emptied into a plastic 25 mL graduated cylinder and volume was measured and recorded into data table 3. A think-stemmed pipet was completely filled with water. Drops were carefully counted and emptied into the empty plastic 25 mL graduated cylinder until the water level reached 1 mL. The number of drops in 1 mL was recorded into data table 3. The thin-stemmed pipet had a total volume of 4 mL and that was also recorded into data table 3.