THE EFFECTS OF BAKING SODA AND VINEGAR By: Ekta Dhanoa Friday, December 22, 2017Research QuestionHow did the concentration of the baking soda (Independent Variable) that was exposed to 5 ml of vinegar affect how much gas pressure (Dependant Variable) was created, as the result of the chemical reaction? This experiment focused on how the reaction rate was affected by the 5 different concentrations of baking soda (0.07 mg, 0.09 mg, 0.11 mg, 0.13 mg, 0.15 mg) and the gas pressure each amount created when the baking soda reacted with the 5 mL of vinegar. Background InformationBaking soda and vinegar are both compounds that create a chemical reaction when they come in contact with each other. Baking soda is also known as sodium bicarbonate, NaHCO?, which is a salt made of sodium ions and bicarbonate ions. Baking soda is an alkali meaning when it comes in contact with any acid, a chemical reaction occurs creating carbon dioxide gas. Vinegar contains acetic acid, CH3COOH (aq). Therefore, when these 2 compounds are combined carbon dioxide is released. The chemical reaction occurs in two steps. First, there is double displacement reaction in which acetic acid in vinegar reacts with sodium bicarbonate to form sodium acetate and carbonic acid. The carbonic acid is not stable, so it undergoes a decomposition reaction to create carbon dioxide and water. (Helmenstine, 2017). The carbon dioxide molecule can then escape from its bonds, through bubbles and fizzing. Concentration affects the reaction rate – speed of which reactants are forming products – of a reaction as it increases the number of collisions occurring. Increasing the concentration of a reactant, increases the frequency of collisions because there would be more particles in a limited space. If collisions are increased, the number of successful collisions are also increased which result in a higher reaction rate. HypothesisIf the concentration of baking soda (Independent Variable – which is exposed to 5 mL of vinegar) is increased then, the gas pressure (Dependant Variable) will increase as well because carbon dioxide is created when baking soda and vinegar react. According to the Law of Conservation of Mass theory, the total mass of the reacting substances is always equal to the total mass of the resulting substances. In theory, if any of the reactants are increased then the product(s) will increase as well. Therefore, if baking soda, a reactant is increased, then the product, carbon dioxide, is also increased, which will result in an increase of gas pressure. Thereby, increasing the reaction rate. Variables Independent Variable: Concentrations of Baking Soda (0.07 g, 0.09 g, 0.11 g, 0.13 g, 0.15 g) – these increments were chosen because they have a definite 0.02 g difference between each allowing the correlation to be seen clearly Dependant Variable: Gas Pressure – measured in kPa by a gas pressure sensor machineControl Variable: Gas pressure of the air (98.14 kPa)Control of Variables: – Amount of vinegar used – was kept at 5 mL for each trial- Human error while reading the graduated cylinder for vinegar – this was minimized by reading the meniscus at eye level- Test tube cleanliness – was kept as constant as possible by washing and drying all test tubes immediately after their use- Size of test tube – was kept constant by using the same test tubeMaterials – Baking soda – a total of 2.75 g is needed – Pure white vinegar – a total of 125 mL is needed- Safety glasses – 1 Scoopula – 1 50 ml Beaker – 1 10 mL Graduated cylinder (± 0.1 mL)- 1 Test tube rack – 5 Test tubes- 1 Electronic weighing scale (± 0.005 g) – 1 Gas pressure sensor with a topper (± 0.005 g)- 1 Phone (to connect with pressure sensor) – 1 Stopwatch (to time the reaction, ± 1 sec.)Procedure0.09 mg of baking soda was measured by placing an empty 50 mL beaker on the balance scale, zeroing the scale and slowly adding little amounts of baking soda into the beaker using a scoopula. 5 mL of vinegar was measured using a 10 mL graduated cylinder, a pipette was used to remove or add small amounts of vinegar to ensure that the final amount was accurate. The meniscus was read at eye level. The 10 mL of vinegar was transferred into a test tube which was placed on a test tube rack. (as in the diagram below)The measured baking soda was poured into the prepared test tube. Immediately after the baking soda was poured the test tube opening was covered with the gas pressure cork top (as in the diagram below) and the timer was started. When 20 sec. were done the pressure was recorded (in kPa) as quantitative data. The liquid was removed from the tube by washing the test tube. Steps 1-5, were repeated 4 more times for the same concentration amount of baking soda and 5 more times for each different concentration thereafter. Results Figure No. 1: Quantitative DataRecorded Gas Pressure of the Chemical ReactionsConcentrations of Baking Soda (± 0.005 g)Amount of Gas Pressure Created(± 0.005 kPa)Trial 1Trial 2Trial 3Trial 4Trial 50.07 g21.08 kPa42.18 kPa34.16 kPa32.96 kPa31.71 kPa 0.09 g44.01 kPa 42.18 kPa 49.07 kPa42.79 kPa42.30 kPa 0.11 g53.88 kPa 52.18 kPa 57.13 kPa 46.33 kPa59.42 kPa 0.13 g63.12 kPa 56.38 kPa 64.50 kPa 67.10 kPa73.79 kPa 0.15 g76.87 kPa70.56 kPa68.87 kPa69.30 kPa76.68 kPaThe data showed that the gas pressure is fairly consistent for every concentration amount. Figure No. 2: Qualitative DataObservations of the Chemical Reactions Concentrations of Baking Soda (± 0.005 g)Observations0.07 gThe mixture was slightly fizzing. It’s increase in height wasn’t as noticeable as it was with higher concentrations. 0.09 gThe mixture fizzed and bubbled. The mixture increased in height a little because of the reaction.0.11 gThe mixture fizzed and bubbled immediately after the baking soda was poured into the vinegar. The mixture increased in height but, slowly descended after a quick second. 0.13 gThe mixture was fizzing and bubbling, it increased in height and descended as quick as it increased. 0.15 gWith this concentration, the mixture raised to its highest height (which was visibly noticeable), this mixture also took the longest to reach its original height. Overall, as the baking soda was poured into the vinegar, the mixture began to foam and produce bubbles at the surface of the liquid. The mixture raised from where it originally started in the test tube but then went down to its original height. The time it took for the mixture to rise and come down decreased as the concentration of baking soda reacting with vinegar was lowered. Figure No. 3: Graph depicting the trends and patterns of the reactionsFigure No. 4: Processed Quantitative DataAverages Gas Pressure of each Concentration Amount Sum of all numbers (heart rate) ÷ Number of subjects = AverageSample Calculation: (21.08 + 42.18 + 34.16 + 32.96 + 31.71) ÷ 5 = 32.41Concentrations of Baking Soda (± 0.005 g)0.07 g0.09 g0.11 g0.13 g0.15 gAverage Amount of Gas Pressure (± 0.005 kPa)32.41 kPa44.20 kPa53.79 kPa64.98 kPa72.46 kPaThe averages of the amount of gas pressure created showed a steady increase as baking soda was steadily increased. Figure No. 5: Processed Quantitative DataReaction Rates of each Chemical ReactionGas Pressure (in kPa) ÷ Time (20 sec.) = Reaction RateSample Calculation: 21.08 kPa ÷ 20 sec. = 1.054 kPa/secConcentration of Baking Soda (± 0.005 g)Reaction Rates(± 0.005 kPa/sec.)Trial 1Trial 2Trial 3Trial 4Trial 5Averages0.07 g1.054 kPa/sec.2.109 kPa/sec.1.708 kPa/sec.1.648 kPa/sec.1.586 kPa/sec.1.621 kPa/sec. 0.09 g2.201 kPa/sec. 2.109 kPa/sec. 2.454 kPa/sec.2.140 kPa/sec.2.115 kPa/sec.2.204 kPa/sec. 0.11 g2.694 kPa/sec. 2.609 kPa/sec. 2.857 kPa/sec. 2.317 kPa/sec.2.971 kPa/sec.2.690 kPa/sec. 0.13 g3.156 kPa/sec. 2.819 kPa/sec. 3.225 kPa/sec. 3.355 kPa/sec.3.690 kPa/sec.3.249 kPa/sec. 0.15 g3.844 kPa/sec.3.528 kPa/sec.3.444 kPa/sec.3.465 kPa/sec.3.834 kPa/sec.3.622 kPa/sec.Figure No. 6: Graph depicting the trends and patterns of the reaction rates Figure No. 7: Graph depicting the reaction rate averagesDiscussionThe results obtained were similar to the expected results. The expected results were that the gas pressure would increase as baking soda was increased, which this experiment showed because the averages of the gas pressure for each concentration amount was increased as the concentration was increased (Figure No. 4). The objective of this experiment was to determine if the concentration of baking soda would affect the gas pressure, resulting in a change of the reaction rate. From the collected data, it can be seen that as the amount of baking soda is increased, the gas pressure was increased as well. In Figure No. 7, the strong correlation between the reaction rate and concentrations of baking soda can be seen very clearly as the line on the graph is linear. There were some possible experimental errors in our plan including human and environmental. Firstly, there was a concave meniscus when measuring the vinegar using the graduated cylinder. This could’ve easily lead to errors because it was difficult to be precise and measure just 5 mL of the vinegar. For the future, if this experiment were to be repeated, it would be suggested that the vinegar be measured using an electronic scale because it would be more accurate and there would a lower uncertainty, increasing the chances of more accurate results. Secondly, some of the test tubes were not properly dried meaning there was still water inside them when the chemical reactions occurred. This lead to complications as the water diluted the reactants, which changed the whole chemical formula of the reaction. Though this didn’t seem like it would lead to problems in the data, (since there were only a few drops of water), it was noticed that the trials where the test tubes were not thoroughly dried had incredibly lower reaction rates (0.07 g – trial 1, 0.11 g – trial 4, 0.13 g – trial 2). This could’ve easily been avoided by drying all the test tubes properly in the procedure or by using different (same size) test tubes every trial. Lastly, some of the baking soda didn’t pour into the test tube, it instead stuck to the bottom of the beaker, so not every single particle of baking soda was used. To fix this, the baking soda could’ve been measured using a non-stick substance, such as a paper napkin, to ensure that all of it was poured into the vinegar for a precise reaction. Most of these errors affected the results producing some ambiguous data. An experiment by Alex Wilkinson’s Science showed the same results as this lab. Though in that experiment the independent variable changed was the concentration of vinegar as opposed to this lab, in which the concentration of baking soda was changed. In the end, Alex Wilkinson’s experiment showed that there is a strong correlation between concentration and reaction rate. As Wilkinson increased the amount of vinegar used on a 10 g of baking soda, the time it took for the reaction to complete increased resulting in an increased reaction rate. Through this lab, it is noticed that the reaction rate is directly correlated with the amount of gas pressure. This can be seen in Figure No. 3 and 6 as one is showing gas pressure and the concentration of baking soda and the other is showing reaction rate and the concentration of baking soda. But, they are both showing the exact same data (graph). This shows that gas pressure is directly related with the reaction rate. From the data of this lab, it can be concluded that there is a strong correlation between the concentration of baking soda and gas pressure. Therefore, there is a correlation between the concentration and the reaction rate (Figure No. 6) proving that concentration is a factor affecting reaction rate. When more baking soda was poured into the limited amount of vinegar the amount of collisions increased. The reactant particles become more crowded, which caused for a greater chance of particles colliding which then lead to an increase in the reaction rate. Also, according to the Law of Conservation of Mass, if any of the reactants are increased then the product(s) will increase as well. Therefore, when the baking soda, a reactant was increased, the product, carbon dioxide, also increased, which resulted in an increase in gas pressure, which increased the reaction rate. Overall, this concentration lab was very compelling, it gave conclusive data that supported the original hypothesis. After doing this lab and interpreting its data, it would be interesting to see how this lab holds with other different reactants. In this lab, baking soda and vinegar was used but, by using other reactants the data would further support or refute this data. For any future extensions of this lab, a lab focusing on different chemicals/solutions and their product(s), would result in more solid and in-depth conclusions. ConclusionTherefore, the hypothesis of “if the concentration of baking soda (which is exposed to 5 mL of vinegar) is increased then, the gas pressure will increase as well because carbon dioxide is created when baking soda and vinegar react” was supported through this experiment. The averages of the gas pressure steadily increased as the concentration of baking soda was steadily increased, which showed that there is a strong correlation between these variables. Since the reactants are increased, the products, carbon dioxide, also increased, resulting in an increase of gas pressure per increment.