Lab 4 – Energy Sources and Alternative Energy Experiment 1: The Effects of Coal Mining |Table 1: pH of Water Samples | |Water Sample |Initial pH |Final pH (after 48 hours) | |Pyrite |6 |6 | |Activated Carbon |6 |7 | |Water |6 |6 | POST LAB QUESTIONS 1. Develop hypotheses predicting the effect of pyrite and coal (activated carbon) on the acidity of water? a. Pyrite hypothesis = The pyrite will probably dissolve a bit and increase the ph of the water b. Coal (activated carbon) hypothesis = The activated carbon will probably increase the ph of the water as it dissolves and releases chemicals into the water 2. Based on the results of your experiment, would you reject or accept each hypothesis that you produced in question 1?
Design Lab-Chemistry HL Date; 27th February and 1st March 2013 Grade 11 Increasing the temperature to increase the rate of reaction between sulfuric acid and iron powder Experiment; To investigate the effect of temperature of reactants on the rate of reaction Focus Question; How does temperature (30, 35,40,45,50 degrees Celsius) affect the rate of reaction of H2SO4 (1.0M, Volume; 20ml) and Fe (2.5g) in 6 minutes? Fe (s) + H2SO4(l) FeSO4(l) + H2(g) Variables; Independent Variable- Temperature Dependent Variable- how much hydrogen gas is produced Controlled Variable-Sulfuric Acid (1.0M, Volume; 20ml), Iron powder (2.5g), and time (6 minutes) Materials; 3 100ml Flasks 1 cork 1 tube 1 100ml graduated cylinder 1 25ml graduated cylinder 1 clamp stand 1 spatula 1 apron A pair of gloves 1 dropper 1 tub of water 1 waterbath 1 balance scale Stopwatch 3 pieces of paper 2 thermometers 37.5 grams of Iron Powder (Fe) 300 ml of 1.0M H2SO4 Procedure; 1. Wear an apron, gloves and goggles for safety reasons 2. Obtain all materials which are 3 100ml flasks, 1 cork, 1 tube, 1 100ml graduated cylinder, 1 25ml graduated cylinder, 1 clamp stand, 1 spatula, 1 dropper, 1 tub of water, 1 waterbath, 1 balance scale, 1 stopwatch, 2 thermometer to your work place 3. Then obtain 37.5 grams of iron powder, and 300 ml of 1.0M H2SO4 to your work place 4.
Course # Student name / Names of members of group Date: Exp # : Estimating the effects of acid rain Introduction: Precipitation that measures a pH value below 5.6 is generally considered as acid rain. Burning fossil fuels is the main reason for the elevated levels of gaseous oxides in a polluted atmosphere that in-turn forms acid rain. Gaseous oxides such as that of carbon, sulfur, nitrogen and phosphorus could dissolve in water to form an acidic solution. A generalized reaction sequence on the formation of acid rain is as follows; One of the determinants of clean water in the natural environment is its alkalinity. Alkalinity can be defined as the capacity to neutralize acids.
Lab 4 – Energy Sources and Alternative Energy Experiment 1: The Effects of Coal Mining |Water Sample |Initial pH |Final pH (24-48 hours) | |Pyrite |7 |4 | |Activated Carbon |7 |8 | |Water |7 |7 | POST LAB QUESTIONS Develop hypotheses predicting the effect of pyrite and coal on the acidity of water? Pyrite hypothesis = If the pyrite is left in a warm climate in water for 48 hrs, then it will have a higher pH then the initial Coal hypothesis = If the Coal is left in a warm climate in water for 48 hrs, then it will have a lower pH then the initial Based on the results of your experiment, would you reject or accept each hypothesis that you produced in question 1? Explain how you determined this. Pyrite hypothesis accept/reject = Reject. According to the pH balance strips, my pyrite recorded a significantly lower pH of 4.
The mixture was refluxed to avoid evaporation while it boiled for 30 minutes. After 30 minutes the mixture was cooled and then filtered through fluted filter paper into a 250ml round bottom flask. The methyene chloride dissolved the trimystrin and would pass through the filter paper leaving the other nutmeg solids behind. The solution was then distilled to get rid of the methlyene chloride and isolate the trimyristin. Methlyene chloride was a good solvent in this case because its boiling point is 40 degrees C and will boil off before the trimyristin which has a boiling point of 56-57 degrees C. Finally acetone was added to wash the crystals and the solution was vacuum filtered.
2: First you measure the mass of the copper tacks and also try to get the mass of the water in the thermos as close to 0.1 kg since 1 dl of H20 = 0.1kg H20. 3: Using the test tube holder, sink the test tube with the copper in it into the 4: The electric kettle is now supposed to make the water boil and raise the temperature of the copper as close to 100ºC (T1cu) but it is not very likely that you will get exact 100ºC due to heat loss. This step will almost certainly take a couple of minutes. 4: Measure the temperature of the water in the thermos (T1w) and then add the tacks to the water in the thermos. 5: Now measure the temperature of the water (T2cu and T2w will have the same temperature).
(b) Calculate the volume of 0.2M UO3- needed to react with 20.00 cm3 of 0.1M Cr2O72-. 3. 24.40 g of hydrated iron(II) sulphate, FeSO4.xH2O was dissolved and made up to 1.0 dm3 of aqueous solution, acidified with sulphuric acid. 25.00 cm3 of the solution was titrated with 20.00 cm3 of 0.022M potassium manganate(VII) solution for complete oxidation. a) Write the equation for the reaction.
It is useful at predicting reactant and product quantities through a reaction. There is enthalpy, Hess’s Law and is related to thermodynamics. It is applied in the real world by adding ice to water, burning fuel for a vehicle, and when power plants pump water into their machinery to keep them cool and not overheat. 2.In an insulated container, you mix 200g of water at 80°C with 100g of water at 20°C. After mixing, the temperature of the water is 60°C.
Calculate the exact normality of Na2S2O3 knowing that in this chemical reaction 1 gram-equivalent of K2Cr2O7 react with 1 gram-equivalent of Na2S2O3 (1 mole K2Cr2O7 react with 6 moles Na2S2O3). Determination of peroxide value. Weigh 3.00 g oil (with precision of 0.001 g) into a 250 ml Erlenmeyer flask. Add 10 ml chloroform and swirl to dissolve oil. Add 15 ml acetic acid,
Therefore we can determine the rate of photosynthesis by the change in oxygen concentration in the experiment. Result: Condition Slope (% O2/min) Photosynthetic Rate (μmol O2/m2/min) Initial phase 0.028 470.60 Middle phase 0.043 722.72 Final phase 0.024 403.38 Dark phase 0.016 268.92 Table 1:slope and photosynthetic rate in different phase Discussion: Setting of the experiment: At the beginning, the oxygen concentration dropped to around 7.85%. it is because one of our group mate do some gentle exercise and we collect the exhaled gas to flush the gas chamber with a higher concentration of CO2. Thus, we can obtain a sharper change during the experiment. The water placed between the light and the chamber act as a cooling agent to prevent absorption of heat of the sample leaf.