-Continue until iodine stays brown. Record time for the starch to be broken down in seconds in the table below. Results Table: pH | Time taken for starch to be broken down by amylase (in seconds) | 3 (acid) | 900 | 5 (slightly acid) | 600 | 7 (neutral) | 240 | 8 (slightly alkaline) | 360 | 9 (alkaline) | | Questions a) Plot a graph of pH on the x-axis and time taken for starch to be broken down (in seconds) on the y-axis. b) At what pH did the enzyme, amylase, work most rapidly? Explain * The amylase worked most rapidly at pH7.
Part E – Deriving a solubility curve Aim: To be able to calculate the solubility of the compound in a certain amount of water as the temperature increases or decreases. Hypothesis: As the water increases, the solubility decreases and the substance’ saturation would get lower. And as the volume increases, the substance won’t separate to the water anymore which makes it dissolved forever without getting crystallized when the water cools down. Apparatus & Method: [refer to the sheet p. 64] Result: Temperature | Volume [ml] | Solubility [g/100g] | 65 ̊ C | 5 ml | 130.44 g | 46 ̊ C | 8 ml | 81.525 g | 39 ̊ C | 11 ml | 59.29 g | 28 ̊ C | 14 ml | 46.586 g | 22 ̊ C | 17 ml | 38.36 g | 16 ̊ C | 20 ml | 32.61 g | 12 ̊ C | 23 ml | 28.35 g | 12 ̊ C | 26 ml | 25.08 g | The solubility was calculated with the formula of: Solubility=6.522gml of waterx 100 The solubility of Potassium Nitrate is directly affected by the temperature of the solution. As the temperature of the solution rises, the solubility of Potassium Nitrate increases.
Equipment List * Boiling Tube * 10 cm3 1mol dm-3 Hydrochloric Acid (HCL) * 15 cm3 1mol dm-3 Sodium Hydroxide (NaOH) * pH and Temperature Probes * Data Logger * Measuring Cylinder ‘ * Boiling Tube * Teat Pipette Method * Add 10ml of Hydrochloric acid, measured in a measuring cylinder, into a boiling tube. * Into a data logger, plug in both pH and temperature probes and switch on data logger. * Put in both the probes and measure both the temperature and pH before adding any other substances. * Add 1cm3 of Sodium Hydroxide, measured in a measuring cylinder, to the Hydrochloric acid, and
3.2 Hypothesis – When the tablet is heated the particles move around faster dissolving the tablet. 3.3 Prediction – The hotter the tablet the faster the tablet will dissolve within the Hydrochloric Acid. 3.0 Experiment Design 4.4 Variables and Controls Type Of Variable | Independent | Dependant | Controls | Characteristics: | Temperature of Tablet | Time taken for acid to react with tablet | * Same size beaker * Same Stopwatch and timer * Same amount of hydrochloric acid * Same number of tablets | Reason | The difference in temperature has been changed deliberately with the Bunsen burner. | The time will vary due to how fast the hydrochloric acid breaks it down. | The variables must be controlled so the experiment is a fair test otherwise the experiment is not accurate.
In this report I will be looking at the effect of temperature in the solubility of sugar (sucrose) in water when it dissolve in different temperature of water and how long it takes to dissolve. I will also use different scientific explanations to support my findings. In order to do this this experiment I have used three different variables which are:- * Independent (temperature) * Dependant( time taken to dissolve) * Control ( volume of solvent and volume of solute) Equipment needed for the experiment is * 100 ml beaker * Sucrose (sugar) * Timer * Tea spoon * Kettle with boiling water * Thermometer * Ice cubes The methods of this experiment are as follows * First I will boil the water at 100 degree and then put the required amount of boiled water in the beaker. * Use thermometer to measure the temperature and record and then add the required amount of solute and start the timer and stirring until it completely dissolves. * Document the time it takes .I will repeat the process three times and take the average amount of time it took for the solute to dissolve in the solvent of high temperature.
Boil at least 10 minutes. 7. While the metal is still in the boiling water bath, measure the temperature of the boiling water carefully with a thermometer and record to tenths, one decimal place, in Data Table 2 8. After the metal has been heating 10 minutes, remove the metal from the boiling water bath using the string. Immediately transfer the metal into the calorimeter cup so that the water covers the metal.
The boiling point can be reduced because of the vapour pressure of it would be the sum of water’s vapour pressure and the compound’s vapour pressure. (http://www.brynmawr.edu/chemistry/Chem/mnerzsto/steam_distillation.htm) According to this experiment, A here is the water and B is the clove. Because liquid boil in atmosphere pressure, so with the existence of water that have boiling point at 100ᵒC, the atmosphere pressure could be reached sooner. The solution resulted from the distillation in this experiment was extracted. To do extraction,
Close the top 5. Put in Thermometer 6. Record starting temperature 7. Use the stirrer to help stir the water and mix it with the sodium chloride 8. Wait until the temperature stops increasing and record the final temperature Data: When the sodium chloride was added to the water, the water started to heat up.
Lab #3/Limiting Reagents Abstract The purpose of this laboratory experiment was to determine whether an unknown compound was sodium carbonate or sodium hydrogen carbonate by reacting a sample of it with hydrochloric acid and comparing the resulting yield of NaCl to the calculated values. The mass of an evaporating dish was taken at the start of the experiment. Then the unknown carbonate A was added in the amount of approximately one gram. The dish was weighed once more to find the definite mass of the unknown carbonate. Then, by means of a dropper bottle and stirring rod, hydrochloric acid was added until all of the unknown carbonate appeared to have reacted.
Buffers work by having molecules bind to free H+( acid) or OH- ( base) to reduce the acidity or basicity of a solution. Why are we using buffers for the pHs of 7 and 9? Buffers are being used for the pH of 7 and 9 in order to maintain a constant pH through the reactions and ensure proper functioning of the enzymes. Without buffers the pH would change and we would not get correct results for our simulated digestive system reactions. Benedicts Solution Iodine Litmus Cream Biuret Reagent What do these