When almost boiling the sand, salt, and benzoic acid it didn’t seem like it was working. I could still see remnants of the benzoic acid floating in the beaker. It seemed like they separated fine, but they never fully dissolved. Then when doing the filtration paper it was also hard because the crystals from the Benzoic acid were already forming making it difficult to get everything out of the cup. It took quite a while for the table salt to dry fully.
One student did not stir the mixture before decanting the water a. This error could cause the percent of sand calculated to be too high. When the mixture is stirred it allows for the sand and salt to separate away from each other enough for the salt to be dissolved and the sand to sink to the bottom. If it is not stirred correctly the salt may not fully dissolve leaving it mixed with the weight of the sand you are using to calculate the percent. b.
4. Chlorine, Cl 2, is a strong oxidizing agent found in bleach. 10.0 cm3 of bleach solution was added to 25.0 cm3 of 0.4M Sn2+ solution acidified with sulphuric acid and made up to 100 cm3. 10.0 cm3 of the resulting solution containing the unreacted Sn2+ was titrated against 0.02M K2Cr2O7. Given that 11.40 cm3 of K2Cr2O7 was required for complete oxidation, a) Calculate the numbers of moles of Cr2O7- used.
I thought distillation would remove the salt. The benzoic acid I wasn’t really sure about. B. If each step isn’t done correctly before moving on to the next step the percent for error rises. C. The sand recovery percentage being higher than the original sand percentage could take place if all the iron was not removed from the mixture.
August 23, 2009 Lab Partner-Joey Stabel The Analysis of Alum K.Schuyler Elvir Malikic Purpose Determining and understanding the characteristics of Aluminum Pre-Lab questions 1) When finding a melting point, why is it necessary to raise the temperature very slowly when approaching the melting temperature? When raising the temperature very slowly it gives the thermometer time to display the accurate temperature of the substance giving you a more accurate reading. Another reason would be the visual of things changing in a slower giving you time to examine what’s happening. 2) Washing soda is a hydrated compound whose
Science Lab Report Problem- To find how to test whether a solution is an acid or a base. Hypothesis- To find whether a solution is an acid or a base, the logical thing to do would be to test the pH level. The reason you would do this is because the higher the pH level is, the more basic/less acidic the solution is. The lower the pH level is the more acidic/less basic it is. Materials- • Litmus paper • Eight different solutions • Latex gloves • Apron • Eye Protection • Paper • Pencil/Pen and • A table (Chart) Procedure- • Use litmus papers to identify solutions • Check color chart to match pH • Fill in table (chart) • Create hypothesis on identity of each solution acidity Chart- (ph levels=0-6-Acid, 8+=Base and 7 is neutral) # ph level What I think the substance is 1 12 Base; identity of substance: Ammonia 2 3 Acid; identity of substance: white vinegar 3 1 Acid; identity of substance: Sulfuric Acid 4 9 Base; identity of substance: Baking Soda diluted with water 5 8 Base; identity of substance: liquid soap diluted with water 6 6 Acid; identity of substance: boric acid 7 2 Acid; identity of substance: Hydroxic Acid 8 11 Base; identity of substance: Ammonium Hydroxide Summary- Therefore, after doing the experiment I was able to determine whether or not each sample of the solutions were acids or bases.
Vapor Pressure and Enthalpy of Vaporization of Water I. List of Reagents: a. Water H2O II. Summary of Procedure: b. Fill a 10 mL graduated cylinder with ≈ 7mL if water c. Fill a 1000 mL beaker with ≈ 750 mL of water d. Invert the graduated cylinder into the beaker.
7. Determine the weight of the salt by subtracting the weight of the empty beaker (step 1) from the weight of the beaker plus the salt
In humans, the majority of the protein found is in the hemoglobin is iron which totals to about 4-6 grams of iron. Obtained from dietary food such ad vegetables, egg-yolk and causes anemia when deficient. Iron tablets contain iron (ii) sulphate . This main aim of this experiment is to determine the percentage of iron in a sample of an iron salt. MATERIALS/APPARATUS: Beaker- 50cm3 Volumetric Flask-250cm3 Conical Flask- Burette-50cm3 Pipette-25cm3 Diammonium Iron (ii) Sulphate 0.1M Sulphuric Acid 0.01M Potassium Manganate (vii) Beaker Digital Balance - 3. d.p METHOD: 5g of Diammonium iron (ii) sulphate is weighed and dissolved into 100cm3 of 0.1M Sulphuric Acid.
The Difference between a Random and Systematic Error A systematic error is a problem that you can't overcome because it's a problem with the experiment itself. For instance, if you're measuring a colour change in a chemistry reaction and you have to rely on your eyes, there's a systematic error there because your eyes are not as reliable as a machine. The error is part of the system...part of the equipment. Or say you have a pair of scales you're using to weigh something, and the scales aren't that reliable? Say they always under-measure by a few grams.