Factors of a reaction lab Essay

Hypothesis According to the collision theory, the rate of a reaction depends on the frequency of collisions between reacting particles. The more frequent the collisions, the faster the rate of the reaction. However, in order for the collisions to be effective, the particles must collide with sufficient energy (activation energy). Furthermore, the particles must collide with the proper orientation. The aim of this lab is to increase how often collisions occur. Theoretically, we should be able to achieve this by increasing the HCl concentration. However, we will instead decrease the HCl concentration just because it’s easier by diluting it with water. We thus predict that by decreasing the HCl concentration, it should take longer for the reaction to produce the predetermined amounts of hydrogen gas that we are observing. Variables Independent- the concentration of HCl Dependent- the rate of the reaction Controlled- Size of test tube Syringe type Timer Mass of Zn Volume of HCl Size of the stopper Controlling Variables size of test tube- we used the same test tube for most of the trials syringe type- we used the same syringe for all the trials timer- we used the same timer for all the trials mass of zn- we kept the mass of zn constant 1.00g size of the stopper- we used the same stopper Procedure 1. Grab a test tube rack, a test tube, a stopper that fits snuggly into the test tube and a syringe. 2. Place the test tube into the test tube rack and attach the syringe to the test tube. 3. Using an electric balance, obtain a sample of powdered Zn that weighs 1.00 g exactly. 4. Pour the 1.00g sample of powdered Zn into the test tube. 5. Grab two beakers. Fill one with HCl and the other with non-distilled water. BE SURE TO LABEL THE BEAKERS APPROPRIATELY! 6. Using a 10ml graduated cylinder and pipette, measure out 10 ml of HCl. 7. Pour the HCl into the test tube, quickly cork the test tube with the stopper, and pull slightly on the syringe’s end to make sure the hydrogen gas will flow through. 8. Record the how long it takes for the marker on the syringe to reach, 1, 2, 3, 4, and 5 cm3. 9. Repeat with HCl concentrations of 0.8 mol dm-3 and 06 mol dm-3. 10. Repeat steps 3-9 a second time in order to obtain a second trial. Data Collection and Processing Raw Data Table Hydrochloric acid, 1.0 mol dm-3 Time taken for corresponding volume of hydrogen gas to be produced/s Volume of hydrogen gas produced/cm3 Observations – Zn clumps together at bottom of test tube – Bubbles are produced – No longer powder – Nothing happens for a while and then all of a sudden there’s like this outward burst of energy which results in small intervals btw the given volumes produced Data Processing Overview I will first determine the average time it took for the different HCl concentration to react and produce the given volumes of hydrogen gas. Next I will calculate the standard deviation for each set of trials to determine the accuracy of the average. Finally, I will graph the average times using a scatter. Sample Calculation Average of different trials for time taken for 1cm3 of hydrogen gas to be produced with 1.0 mol dm-3 of HCl: (118 + 123)/2 = 120.5s Hydrochloric acid, 1 mol dm-3 Volume of hydrogen gas produced/cm3 Average time taken for corresponding volume of hydrogen gas to be produced/s 1 120.5 2 152.0 3 190.5 4 227.0 5 274.0 Hydrochloric acid, 0.8 mol dm-3 Volume of hydrogen gas produced/cm3 Average time taken for corresponding volume of hydrogen gas to be produced/s 1 137.0 2 226.0 3 330.0 4 439.5 5 552.5 Hydrochloric acid, 0.6 mol dm-3 Volume of hydrogen gas produced/cm3 Average time taken for corresponding volume of hydrogen gas to be produced/s 1 202.0 2 209.0 3 242.0 4 309.5 5 382.5 Standard deviations of the averages were determined by using the following formula in a Microsoft Excel program: Standard Deviation for different HCl acid concentrations HCl acid concentration/mol dm-3 Standard Deviation Average time vs. Volume of hydrogen gas produced Conclusion and Evaluation Conclusion: – Hydrochloric acid, 1 mol dm-3 concentration, the highest concentration used in this experiment produced the given volumes of hydrogen gas the fastest out of all three HCl concentrations. – Hydrochloric acid of 0.8 mol dm-3 concentration did produce 1 cm3 of hydrogen gas faster than hydrochloric acid of 0.6 mol dm-3 as predicted. – Hydrochloric acid of 0.6 mol dm-3 concentration produced hydrogen gas faster than hydrogen gas of 0.8 mol dm-3. – Limitations Suggestions for Improvement Some of the Zn powder got stuck to the side of the test tube as we poured it into the test tube. Maybe use a straw or something like that to make sure the Zn gets to the bottom of the test tube. And like blow into the straw (softly!) to ensure that none of the Zn gets stuck to the inside of the straw. We didn’t use the same syringe for all the trials because we were trying to get all the trials in on the same day. Use the same syringe for all trials. We didn’t get all the trials in on the same day. I think it took us three classes. As a result, each day we were working in different room temperatures. Organize ourselves better so that we get all the trials in on the same day. We couldn’t dry the test tube correctly. Each time we dried it there was still water at the bottom of the tube. Maybe like attach a paper towel to a stirrer and swap it around inside the test tube to dry it out. Zn is impure. As a result, the HCl acid could be reacting as well with whatever impurities present are thus slowing down the reaction, perhaps.