Molar Mass Lab

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

In experiment 3.11, we found out whether or not a larger amount of a liquid would get hotter when it boils. To answer this, we heated a specific amount of unknown liquid and recorded the temperature every fifteen seconds. In our scatter plot, we were able to find the boiling point of our liquid. We know that the slope of our graphs is when the liquid molecules were moving around and heating up. The plateau of our graph points is where the liquid started to evaporate and boil. This is were we found our boiling point at. Shantel and I decided that our boiling point was about 98º Celsius. If you had another slope in your graph, that was when you were simply heating the leftover gas. The histogram showed us that there were about equal amounts of data in the higher temperature (about 95º Celsius) bins for both 20mL of liquid and 10mL of liquid. Also, in the lower temperature bins (75º to 80º Celsius) there was about equal amount of data for 20mL of liquid and 10mL of liquid. There was 7 pieces of data for 10mL of liquid in the lower bins, and 6 pieces of data for 20mL of liquid. If a larger amount of liquid did have a higher boiling point, the clusters would be organized by volumes or amount. For example, all of the 20mL pieces of data would be in the higher temperature bins, and all of the 10mL pieces of data would be in the lower temperature bins or flipped. Rather, the bins were clustered by identity. The boiling point is a characteristic property.

Substances A and B have an appearance of a white solid like. Substances A and B were put into a test tube and on the Bunsen burner. As a result, B melted faster than A. A was slow to melt. The reason why B melted faster than A is because it has a lower boiling point than substance A which made it melt faster. It also shows that A needs more energy than B to be broken down.

Distillation is a method of separating two volatile chemicals on the basis of their differing boiling points. During this lab, students were given 30 mL of an unknown solution containing two colorless chemicals. Because the chemicals may have had a relatively close boiling point, we had to employ a fractional distillation over a simple distillation. By adding a fractionating column between the boiling flask and the condenser, we were able to separate the liquids more efficiently due to the fact that more volatile liquids tend to push towards the top of the fractionating column, thereby leaving the liquid with the lower boiling point towards the bottom. After obtaining the distillates, we utilized a gas chromatograph in order to analyze the volatile substances in the gas phase and determine their composition percentage of the initial solution. Overall, through this lab we were able to enhance our knowledge on the practical utilization of chemical theories, and thus also demonstrated technical fluency involving the equipment.

Determining the Molar Volume of a Gas Anita Lau Partner: Anthony Yuen Ms B. IDC4U 24 April, 2015 Purpose: In this experiment, the molar volume ( the volume occupied by one mole of a gas) of hydrogen gas at standard temperature and pressure is measured. According to Avogadro's Law, at the same temperature and pressure, equal volumes of gases contain the same number of molecules. Therefore the volume of any given gas must be proportional to the number of moles of molecules present when the temperature and pressure are constant.

Table 1: The following table shows the mass of quartz prior to experimentation and then after experimentation for quartz. Sample number Initial mass (g) Final mass (g) Material Remaining (%) Quartz 1 33.50 33.40 99.70% Quartz 2 31.80 31.80 100.00% Quartz 3 42.80 42.80 100.00% Quartz 4 37.10 37.10 100.00% Quartz 5 23.00 23.00 100.00% Quartz 6 7.90 8.00 101.27% Quartz 7 19.50 19.30 98.97% Quartz 8 14.50 14.50 100.00%

One source of error could be that there were some air bubbles present in the graduated cylinder when we released gas into it. With air bubbles remaining in the cylinder, the volume of butane measured would be higher than the actual volume. The mole of butane would then be higher. Thus, the molar mass of butane would be smaller than theoretical molar mass.

The topic examined in Lab 4 is how Body Mass, Brain Size, and Life History variables, are distinct amongst humans, apes, and other primates. These variables are related because they demonstrate positive correlations in the scatterplots of Age of First Reproduction (years), Maximum Lifespan (years), and Observed Brain Size (cc) of the species, in relation to an increasing Body Mass (kg). By examining these variables, the Encephalization Quotient (EQ), Age at First Reproduction, and Maximum Lifespan are then compared amongst humans and various apes. It is suggested that the EQ, Age at First Reproduction, Maximum Lifespan of humans are higher than other apes.

In 1909 S.P.L. Sorensen published a paper in Biochem Z in which he discussed the effect of H1+ ions on the activity of enzymes. In the paper he invented the term pH to describe this effect and defined it as the -log[H1+ ]. In 1924 Sorensen realized that the pH of a solution is a function of the "activity" of the H1+ ion not the concentration and published a second paper on the subject. A better definition would be pH=-log[aH1+ ], where aH1+ denotes the activity of the H1+ ion. The activity of an ion is a function of many variables of which concentration is one. It is unfortunate that chemistry texts use a definition for pH that has been obsolete for over 50 years.

The average Molar Volume of di-hydrogen based off the results of the experiment was calculated to be 22.4025 (refer to table 2). Compared to the molar volume of an ideal gas, 22.4, the percent error is a relatively low 0.0107% (refer to table 2). This was calculated by conducting an experiment to find the pressure of a Magnesium/ Hydrogen Chloride reaction (Magnesium set as limiting reactant). The pressure was then integrated into the equation V = R(nT/P) along with the preset values calculated from the experiment. The volume was calculated, then was integrated into the proportion equation; (V1)(P1)/(T1) =

Foor this you simply have to take a look at the processed data table and graph. There is a clear specific trend, visibly recognizable as well as mathematically (a trend line indicates it), that is, as the molar concentration (solute) of salt increased in the solution where potatoes were placed, the mass of potatoes decreased. Now, from the molar concentrations of salt solute that we tested (0.0M, 0.2M, 0.4M, 0.6M, 0.8M, 1.0M) we cannot decipher with certainty and accuracy what is the molar concentration of potato cells. However, we can estimate, and judging by the a decrease in percent mass from 21.10% grams (0.0M) to 12.13% (0.2M) and followed by a constant decrease in percent change in mass, it can be said that the salt concentration of a potato cell is between 0.0M and 0.2M. This is because these molar concentrations are the one that show the decrease in mass of the potato. When there’s a decrease in mass, this practically means that the water inside the cells is leaving because of diffusion to areas of lower concentration.

The three fluids used in the first part of the lab and whose densities and other properties were calculated.

The mole is equivalent to 6.022 X 10²³, which indicates how much particles of element is in one gram. The molar mass can be found in the atomic mass from the periodic table. The Lab 11 involves how much oxygen (O) magnesium (Mg) combines through combustion and form Magnesium Oxide. The magnesium strip of unknown mass was used as main ingredient for experiment. The lab also requires crucible with cover, crucible tongs, ring pad, and Bunsen burner.

In the third stage of this experiment, the density of a liquid was determined and compared to known standards. A 100ml beaker was filled to about half-full with room-temperature distilled water. The temperature of the water in ◦C was recorded in order to compare to known standards later. A 50ml beaker was then weighed on a scale in order to determine mass and recorded. A sample of the distilled water with an exact volume of 10ml was then placed in the 50ml beaker using a volumetric pipette. The 50ml beaker with the 10ml of water was then weighed again and the initial mass of the beaker was subtracted from this mass to obtain the mass of the 10ml of water. With the volume and the mass of the water now known, density was calculated using d = m/V and recorded in g/ml. This process was then repeated to check for precision and compared to standard values to check for accuracy. Standard values were obtained from CRC Handbook, 88th Ed.

In practice, the molecular mass (M), of a compound is the sum of the atomic masses (atomic weights) of the atoms as given in the molecular formula. For instance, the Molecular Mass (M) of the compound carbon dioxide is