Everything can change from one substance to another, but the creation and the end of some things never happen .On a beautiful day on the fourth of December in 2015, the class of SNC1D5 started a lab on different kinds of molecules. The reason why we did this lab was to investigate the chemical and physical changes between different substances. Substances can change from one substance to another that have alternate physical and chemical properties by chemical reactions or with reactants or with heat. A physical change mixes up molecules but doesn’t hurt their inner structure. An example of physical change is ice turning into water due to heat because it didn’t change the substance’s material. A chemical change occurs when there’s a new arrangement
They tested how the temperature would affect the rate of reaction. This was observed by the amount of time it took for the solution to change colors. For many chemical reactions there is an optimum temperature at which the chemicals will react with each other. As was found in their experiment, the temperature affected the rate of reaction. (Deoudes, 2010).
The results do not support the hypothesis that a higher surface area to volume ratio would result in sulphuric acid being diffused into the agar cubes in the shortest amount of time. This is evident in the results as the exact opposite to what was predicted occurred. Instead of the smallest cube with the largest surface area to volume ratio of 1cm3 having the quickest diffusion rate, it conversely took the longest at 0.092 cm3 per second, whilst the 2cm3 cube with 0.0384 cm3 per second took the least amount of time. This directly refutes the hypothesis. There was also no consistent trend evident in the results. Between the two largest blocks of 2cm3 and 3cm3, there was only a 0.00243 cm3 per second, however, and in contrast to the hypothesis,
The control in the experiment is water. Units used while timing the productivity of gas from an Alka-Seltzer tablet in different temperatures is, seconds. In order to find out if temperature controls the rate of chemical reaction, whether hot water is a more effective way to make the gas produce at a faster speed, it would be necessary to compare the results of different temperatures at the end of each trial. In order to do this the scientists will measure the volume of gas that is produced within a 10 second interval time after the tablet begins to react.
The experiment that was done was to figure out “Does the amount of calcium chloride affect the temperature of water?” For the procedure, the experiment asked to record the initial temperature of 75 mL of water. The first trial said to add zero scoops of calcium chloride and stir for two minutes to record the temperature. Once the first temperature was recorded, it must be written from the difference between the initial temperature and the new temperature. Next, it asked to add one scoop of calcium chloride and stir for two minutes and record.
In the first part of the experiment, Part A, the standard solutions were prepared. As a whole, the experiment was conducted by four people, however, for Part A, the group was split in two to prepare the two different solutions. Calibrations curves were created for the standard solutions of both Red 40 and Blue 1. Each solution was treated with a serial 2-fold dilution to gain different concentrations of each solution.
For example, an experiment similar to this one could be how pressure could affect the time it takes for an Alka-Seltzer tablet to dissolve. Using A flask and rubber stoppers, you can compare the amount of time it takes for and Alka-Seltzer tablet to dissolve in regular room temperature water and room temperature water in a flak but with a rubber stopper stopping the air flow into the flask. This is related to the experiment performed above because the increase in pressure from the rubber stopper stopping the air flow in and out of the flask may affect the time it would take for the Alka-Seltzer tablet to dissolve. Another example of an experiment related to the one performed above is how the amount of water used to dissolve an Alka-Seltzer tablet effects the time it takes for one to dissolve. This also relates to the experiment performed above because it also affects how fast the rate of reaction is.
The dependent variable, which is the time taken for the empty muffin paper cup to touch the ground (immediately after it was dropped). This will be measured using a stopwatch, which will start when the paper cup is dropped, and stopped when the paper cup touches the ground. This will be done on table, preferably inside a science laboratory. (The table will be parallel to the muffin paper cup).
Identify the independent Variable Size of the tablet Identify the dependent Variable Reaction time List the controlled variables The solution (water), temperature, volume of water (200 mls) The amount of Alka- Seltzer How will the dependent variables be measured A stop watch will be started as the pieces of Alka-Seltzer are dropped into 200ml of room temperture water Describe the expected results if the hypothesis is true The 3 smaller pieces of Alka Seltzer will dissolve quicker than the ½ tablet .
Repeat steps 1-10 for two more trials. Conclusion: 1. I chose to compare temperature and amount of reactants in my experiments. I chose these because I thought they would reveal the the most drastic time differences. I also chose these factors because I had prior knowledge of them before I even started chemistry.
The purpose of this lab is to observe the reaction between hydrochloric acid and magnesium metal. When the substances are reacted over water, the products produced are a salt in aqueous solution and a gas. While the salt remains in the water as part of a solution, the gas produced will float to the top. Though water vapor pressure will affect the pressure of the gas in the eudiometer, it is possible to apply Dalton’s law of partial pursues to find the dry pressure of the gas. When the dry pressure is determined, the volume of the gas at STP can then be determined and what the experimental volume of one mole of the gas would be at STP.
Dependent The time taken for the bluish -black color to fade away (color of Iodine solution mix with starch solution ). The rate of enzyme reaction Minutes (min) Table 1.1 – Table shows the controlled variables in the experiment variables Units Measures of controlled variables.
CLAIRE MUNTING 29/01/2018 Criterion C EFFECTS OF SURFACE AREA OF CALCIUM CARBONATE UPON RATE OF REACTION Calcium Carbonate Chips 1 Introduction: Within the current investigation, the effects of the surface area of Calcium Carbonate (CaCO3) in combination with Hydrochloric acid (HCl) upon its rate of reaction. CaCO3, commonly referred to as limestone, is an organic substance and is, in a sense, the crystallised “carbonic salt” of the element, calcium2. In addition to being a salt, the pH level of Calcium Carbonate is 9.91, and it is therefore, a basic substance, due to the fact that it is comprised of a pH level higher than 7, which is neutral3. HCl, however, is the bodily acid found in the stomach of human beings.