- Join over 1.2 million students every month
- Accelerate your learning by 29%
- Unlimited access from just £6.99 per month
International Baccalaureate: Chemistry
Meet our team of inspirational teachers
Which fruit juice (Orange, Apple, Peach, Pineapple, and Apricot) has the highest concentration of ascorbic acid?
Graduated cylinder 3. 100 milliliters of dichlorophenolindophenol (DCPIP) indicator solution 4. Burette 5. Distilled water 6. Funnel 7. Conical flask 8. Beakers PROCEDURE: 1. Gather your materials. 2. Set Burette onto stand with clamp. 3. Fill a graduated cylinder with 10 mL of distilled water and pour into a beaker. 4. Fill a graduated cylinder with 10 mL of Apple Juice and pour into the beaker with distilled water. 5. Mix the solution and put the solution in a 100 mL conical flask. 6. Put the conical flask aside.
- Word count: 1091
1. dilute hydrochloric acid (0.5 mol/L) 2. spark lighter 3. Bunsen burner clamped to a retort stand 4. paper towel 5. wooden splint 6. masking tape or test-tube stopper Procedure Part A: Reactivity of Metals in Water The materials were selected and brought to the station. Safety protocol was followed and safety glasses were worn throughout the experiment. The appropriate data tables were drawn in which to record the data observations. The beaker was filled with approximately 250 mL of tap water. The water was tested with pH paper and the results were recorded. On a folded piece of paper towel, the professor placed a small piece of calcium (Ca).
- Word count: 1929
When the magnesium oxide powder was added to the hydrochloric acid, there was no immediate reaction 2. When stirring with the temperature probe, the magnesium oxide slowly started to dissolve heating up as it went along 3. In the end, there were still some clumps in the solution but it had reached maximum temperature Calculations: Trial 1 Calculations for the heat of formation for Mg(S) +2HCl (aq) →MgCl2 (aq) +H2 (g) Table 3: Uncertainty Calculations Uncertainty Calculations Absolute Uncertainty Percent Uncertainty Initial temperature Final temperature 22.1°C ±0.2°C 27.4°C ±0.2°C âT = 5.3°C ± 0.4°C âT = = 7.54% Mass of HCl heated 100.00g ± 0.01g ±0.01g ±1.00% Total uncertainty of Q 7.54% + 1.00% = 8.54% Moles of magnesium(Mg)
- Word count: 2206
3. 4. Now, we can use q=mc ?T to calculate the energy gained by the solution: 1. 2. 3. Therefore: 1. Now, we have to calculate the number of moles for MgO: 1. 2. 3. We can now calculate the change in enthalpy by dividing the q of the reaction by the moles of the limiting reagent: 1. Now, we do reaction 2, trial 1 so we can use Hess?s law to calculate the change in enthalpy of formation, but first we are going to calculate the uncertainty in this expression: First, we calculate the uncertainty for the: 1.
- Word count: 11607
Copper stripe is the positive electrode. Zinc stripe is the negative electrode. Reaction happened on each terminal: Positive terminal: Zn-2e-Zn2+ Negative terminal: 2H2e-H2 It is assumed that bubbles (hydrogen gas) will come out from copper electrode. It is assumed that zinc and copper stripes are pure. Classification of variables Dependent variables Current of the voltaic cell Independent variables Concentration of sulfuric acid solution Controlled variables Size of the copper and zinc stripes Material of the electrodes Distance between the electrodes during reaction Volume and temperature of sulfuric acid solution Materials and Apparatus 1cm4cm Cupper stripes 1cm4cm Zinc stripes 1 Ammeter () 2 Wires 2 Beakers () 9molL-1 H2SO4 ( 1 Cylinder (25mL)
- Word count: 907
Therefore, combustion occurred, since the water vapour means that H2O and CO2 are produced as bi products. The combustion almost complete, but not quite, since the black smoke suggests that a small amout of noxious CO and carbon were also produced. When the lighted splint is applied to the basin full of hexane, the whole surface of the alcohol catches fire (combusts) and a big flame forms, which lasts circa 5 minutes. As the fire blazes, some black smoke rises from it, and the walls of the evaporing basin become first light brown, and then progessively a darker shade of brown.
- Word count: 2623
In this lab, we will use the sodium hydroxide to determine the percent acetic acid in vinegar using titration.
In titration labs we assume that the number of moles of the base is the same as the acid?s: 1. 2. 3. Now we multiply the volume by the molarity: 1. 2. Got the molarity from the previous lab 3. Assuming that the moles of OH- = H+ we just multiply the moles by the molar mass to give the mass of acetic acid: 1. 2. 3. Now we divide the mass of acetic acid by the mass of the vinegar and then multiply it by a hundred to get the percentage.
- Word count: 1254
Record the mass of the calorimeter 4) Fill the calorimeter approximately half full with distilled water at room temperature and record the mass and temperature 5) Add the metal carefully into the beaker and wait at least 10 minutes before doing anything. 6) While the metal is still in the boiling water, measure the temperature of the water with a thermometer and record. It will be assumed that the temperature of the metal is the same as the boiling water. 7) After the metal has been heating 10 minutes, remove the test tube from the beaker.
- Word count: 536
Small changes in pH can endanger many kinds of plants and animals; for example, trout and various kinds of nympH s can only survive in waters between pH 7 and pH 9. If the pH of the waters in which they live is outside of that range, they may not survive or reproduce. Changes in pH can also be caused by algal blooms (more basic), industrial processes resulting in a release of bases or acids (raising or lowering pH ), or the oxidation of sulfide-containing sediments (more acidic).
- Word count: 1670
1.350 1.300 1.350 ±0.025mA 3mA 0.5 M CHâCOâH (Acetic acid) 0.850 1.000 0.900 ±0.025mA 3mA Distilled water 0.0500 0.0550 0.0500 ±0.0025mA 0.3mA Table 1 above shows the raw data of experiment I did to test the strength different electrolytic solutions. Moreover, this data table shows that all solutions except tap water and distilled water have the concentration of 0.5 M. In this table, some solutions’ ammeter reading has different uncertainty and multimeter setting. This is because solution like hydrochloric acid has high amp, so I had to set multimeter setting at 300mA in order to measure the ammeter reading of hydrochloric acid accurately.
- Word count: 980
Pour 5cm3 of HCl into the eudiometer. Then carefully filling the eudiometer with water above the HCl, without mixing the liquids. 3. Wind the magnesium ribbon around a piece of copper wire and let it hang down a little bit into the eudiometer. Make sure there is a hole into the rubber stopper and fill it with water. 4. Place a large measuring cylinder filled with water in the sink. Put a finger over the hole in the stopper and turn the eudiometer upside down into the cylinder.
- Word count: 717
Dry your egg shell with a paper towel and put it into a beaker. 3. Dry the shell further either in an oven or by using hot air from a hair dryer. 4. Grind the shell to a fine powder with a mortar and pestle. For the next few steps your setup should look like this: 1. Weigh accurately 0.5g of the power in a conical flask. 1. Use a mortar and pestle to powder the eggshell. Powdering will increase the rate of reaction and will result in the time for the experiment to occur to reduce.
- Word count: 1166
different type of food (mushrooms, potatoes, bread piece, sweet potatoes, lemon, onion, biscuit, cucumber, tomatoes, peanuts,lettus, tomato sauce, dark green vegetables, milk, cereal), white tile Ten test tubes, test-tube holder, test-tube rack, Nusen burner, Heat-proof mat, safety glasses Procedures: 1. Three drops of 2cm3 of 1% starch solution was placed onto a white tile and three drops of iodine solution was added and observed the solor change. 2. 2cm3 of glucose solution was placed into a test tube and added about five frops of Benedict?s reagent and boiled gently.
- Word count: 890
Percent Yield Lab. This experiment has proven that KI is the limiting reagent in this chemical reaction.
This calculation is performed twice once for the first reactant and one for the second. Then the Theoretical Yield is calculated, it is how much product will be synthesized with the reactants. Multiply the lowest number of moles (limiting reagent?s mole) by the molar mass of the product. This will give you the mass of the product. In order to find the percent yield, a ratio between the actual yield and the theoretical yield is used. This indicates the percent of how much of the theoretical yield was obtained in the experiment.
- Word count: 1671
Using this information, a calorimetric lab was conducted to find the molar enthalpy of neutralization for the sodium hydroxide solution. Through molar enthalpy calculations, the experimental molar enthalpy of neutralization for the sodium hydroxide solution was found to be -64.0±3.3KJ/mol; however, the theoretical (actual) molar enthalpy of neutralization for the sodium hydroxide solution is -57KJ/mol. In other words the experimental enthalpy change was -64.0±3.3KJ and the theoretical (actual) enthalpy change was -57KJ. This as a result produced a 12% difference.
- Word count: 1351
However, when the base is added and the endpoint has been reached, the color changes to yellow. If over titration occurs, the solution will still remain yellow. 16.90 17.20 0.3 17.20 17.40 0.2 17.40 17.60 0.2 17.60 17.80 0.2 Methyl Red 0.00 5.00 5.0 The indicator is red-pink at first when added to the acetic acid. However, when the base is added and the endpoint has been reached, the color changes to a light orange shade. If over titration occurs, the solution will change yellow. 5.00 7.80 2.8 7.80 10.70 2.9 10.70 13.60 2.9 13.60 16.50 2.9 Bromocresol Green 20.80 21.20 0.4 The indicator is yellow-green at first when added to the acetic acid.
- Word count: 3941
Energy Change in a chemical reaction. Throughout this investigation I will try to figure out the energy difference between different compounds reacting with water in a solution while it is being heated up.
Variables Independent Variables Temperature (This variable was controlled to keep the three separate experiments valid as the experiment was conducted to figure out the factors that affected the rate of which energy is transferred through a reaction so this variable must be kept equal. Dependent Variable Time (This variable was dependant on the temperature as it was one of the factors that was investigated upon as the experiment was conducted to figure out the factors to which affect the amount of time that it takes the solution to reach a particular temperature) Materials - (3) Beakers (250ml) -Hydrochloric acid (10ml)
- Word count: 773
Aim: To identify the limiting reagent in the reaction on the basis of practical and theoretical yield
weight 20.75gms of potassium iodide on an electronic balance 2. put potassium iodide in a round bottom flask 3. add 250 cm3 of water to the flask to make solution of 0.5 molar concentration potassium iodide 4. weight 16.6gms of lead nitrate on an electronic balance 5. put the lead nitrate in a round bottom flask 6. add 100 cm3 of water to the flask to make 0.5 molar concentration of lead nitrate 7. using a pipette take 10 cm3 of lead nitrate and place it in a conical flask 8. using a pipette take 5 cm3 of potassium iodide and place it in the conical flask containing 10 cm3 of lead nitrate 9.
- Word count: 522
Titration lab report. Aim: to determine the quantity and concentration of NaOH to completely neutralize one molar hydrochloric acid till the n point.
required of neutralize acid (0.5 molar HCl). From the results we would know the quantity required to neutralize the acid also the quantity can be used to calculate the concentration of NaOH. Control Variable Dependant variable Independent variable 1. Concentration of HCl and NaOH 2. Temperature 3. Pressure 4. pH of HCl 1. Volume of NaOH 1. colour of HCl Method: arrange burette, stand and clamp in the following way and place the conical flask 1.
- Word count: 434
Experimental Design You will burn two identical strips of magnesium in ceramic crucibles. The contents of one crucible will be analyzed as they are. In the other crucible, any magnesium nitride that may have formed will be chemically converted into magnesium oxide. You will then determine the mass of the product in both crucibles and use this value to calculate the percentage composition of magnesium oxide. You will compare the two calculated values. Materials 1. 2. Chemical safety goggles 3. Ceramic crucible and lid 4. Balance 5. Ring clamp 6. Bunsen burner clamped to the retort stand 7.
- Word count: 1496
of acid,Na=mass of the acid/molar mass of the acid mass of the acid,Ma=molar mass of the acid number of moles of the acid molar mass of the acid: Mr(C6H5COOKCOOH)=6(12.01)+5(1.01)+12.01+2(16.00)+39.10+12.01+2(16.00) +1.01 =205.24 Hence,the mass of the acid,Ma=0.0250 205.24 =5.131g to 3 decimal places Results Table: RESULTS mass/g uncertainty/g` mass of weighing bottle and acid 39.01 +/-0.01 mass of weighing bottle 33.88 +/-0.01 mass of acid 5.13 +/-0.02 Concentration of the acid,Ca=number of moles of the acid/volume of the acid =0.0250 1000/250.00 =0.100 Error propagation sources of error % error calculation mass of the acid =0.02/5.13 =0.4 volume of solution made in
- Word count: 2311
Thus, we get: = PKa + = PKa Now the PH was, so PKa= 5.0 ±0.1 = 5.0 ± 2% 5.0 ±2% = = 10-5 ±2% Titration curve: To get error we are going to sketch a titration curve, and from this measure the PH at half equivalence. To do this: PH of acetic acid (1M): Ka = = 10-4.76 = √(1×10-4.76) So PH of acetic acid= 2.38 Now PH of NaOH, (1M) Now concentration of NaOH, was 1M So = 1 = -log(1)
- Word count: 1985
subtracting the initial temperature from the finial temperature Step 6: Repeat steps 1-5 8 more times for a total of 9 trails changing the mass of Mg in step 4 every 3 trails from 0.02g ± 0.001g to 0.03g ± 0.001g to 0.04g ± 0.001g. Data Trail/Mg Mass Trail 1 0.02g ± .001g Mg Trail 2 0.02g ± .001g Mg Trail 3 0.02g ± .001g Mg Trail 4 0.03g ± .001g Mg Trail 5 0.03g ± .001g Mg Trail 6 0.03g ± .001g Mg Trail 7 0.04g ± .001g Mg Trail 8 0.04g ± .001g Mg Trail 9 0.04g ±
- Word count: 695
Measuring the fatty acid percentage of the reused sunflower oil after numerous times of potato frying and determining the effects of it on human health.
are created in an industrial process that adds hydrogen to liquid vegetable oils to make them more solid. As they do not exist naturally, trans-fats are difficult to metabolize and so they accumulate in the fatty tissues of the body. They also cause an increase in the levels of LDL (bad) cholesterol and a decrease in the levels of HDL (good) cholesterol, which can lead to atherosclerosis (narrowing of the arteries) and a resultant increase in the probability of strokes and heart problems. LDL is low-density lipoprotein; HDL is high- density lipoprotein. Their density is determined by the amount of proteins present in the molecule.
- Word count: 6618
Therefore, the following relationship holds: nVb x Cb = Va x Ca Where: Vb = the volume of the base Cb = the concentration of the base Va = the volume of the acid Ca = the concentration of the acid n = the mole factor In the case of hydrochloric acid and Sodium Bicarbonate (Baking Soda), the mole ratio is one to one, thus the mole factor is 1. Therefore, the volume of sodium bicarbonate multiplied by its concentration in molarity is equal to the moles sodium bicarbonate.
- Word count: 1803