I. INTRODUCTION This report discusses an experiment, the objective of which was to determine the classification of six known chemicals: sodium nitrate, barium chloride, silicon carbide, naphthalene, urea, and antimony and two unknown chemicals XIa and XIb. Since each type of chemical (ionic, molecular, macromolecular and metallic) has its own set of properties, by testing these properties and finding them out for each chemical, it was possible to classify them. The properties tested during this experiment were solubility in water, toluene, and ethanol and the electrical resistance for those soluble in water. The melting point was tested for the two unknown chemicals.
Once AMD reached the coveted pH level, it was filtered using filter paper (0.45 μm) to obtain the precipitate. The filtrates were then measured for the EC level using conductivity meter, TDS level using TDS meter, and concentration of Cu2+ using PerkinElmer Atomic Absorption Spectroscopy (AAS) Analyst 400. All analyses were conducted in Analytical Chemistry Laboratory, University of Mataram. Filtrates (with several pH levels) found to still contain Cu2+, would be treated to the sulfidization treatment. Sulfidization treatment using SNW from Sebau This experiment was conducted by adding pure SNW from three sampling points (T1, T2, and T3) to the AMD with three different pH levels in 1:1 ratio reaction.
Sodium hydroxide, a very common base, is another common example of secondary standard. It is very hygroscopic, meaning that it absorbs water from the air, also meaning that its mass basically changes while you 're measuring it. Since it can 't be measured reliably, it can 't really be used as a primary standard. But it can be titrated against a primary standard, and thus can be used as secondary standard. To standardize a solution, a titration is done with primary
However, any doubts regarding the results may be traced to a few elements of the experiment that lend themselves to possible error. The following factors may have contributed to potential errors in the experiment; the need to zero the machine between each of the readings in obtaining the absorption spectrum and the resulting peak wavelength, the precision with which a person can accurately adjust the needle on the spectrophotometer to zero is limited, not putting in the inaccurate amount of cobalt chloride or water into the substance, and getting oil from our fingers onto the
We observe whether it dissolves in a given solvent or whether it evaporates if exposed to the atmosphere. We might get some sense of its density by seeing it float or sink when added to an immiscible liquid. These are qualitative observations, but they provide an important foundation for further experimentation. It is only a modest extension of direct observation to the use of some simple experimental apparatus for quantitative measurements. We use a heat source and a thermometer to determine melting and boiling ranges.
Introduction Buffer is a solution that resists a change in pH when bases or acid are added. Solutions that are acidic contain high concentrations of hydrogen ions (H+) and have pH values less than seven. Buffer usually consist of a weak acid, and its conjugate base or a weak base and its conjugate acid. The function of buffer is to resist the changes in hydrogen ion concentration as a result of internal and environmental factor. This buffer experiment is important so that we relies the important of buffer in our life.
CH 204 - Introduction to Chemical Practice Experiment 2 - Qualitative Analysis of Cations Petra Hsia Stefi Hsia TA: Joey Gurrentz February 8, 2018 RESULTS & DISCUSSION In Part A of the experiment, the presence of silver was confirmed by the "Unknown 4" substance. It was discovered with two rounds of testing. In the first round, two drops of 6M acetic acid and 4 drops of 1M K2CrO4 was added to the "Step 6" test tube, the solution turned a yellow-orange color. Because there was no formation of yellow precipitate, it was confirmed that lead was not present in the solution. Since lead was not present, the "Part A" test tube, which contained precipitate from the "Unknown 4" substance, was now to be tested for the presence of silver.
In this particular experiment, an Sn2 reaction occurred because the unknown nucleophile attacked the atom that was negatively charged, the alkyl bromide. Once the bromide left with an electron pair, the nucleophile replaced it and the result was a product of benzyl ether. 5. Melting point was used to determine the impurity of the synthesized product through comparing it’s melting range to the melting ranges of the given compounds. This was done through mixed melting points technique whereby two compounds, one that is known and one unknown, were mixed together.
In electrolysis, current flows through a molten ionic compound or an ionic solution because both of them contain free mobile ions that can move around and gain or loose electrons. Covalent compounds can not be used in electrolysis because they contain molecules which are neutral (while ions are charged) hence they can not be discharched at the electrodes as they don’t gain or lose electrons at the electrons due to their neutral charge. For electrolysis: a current source, electrodes and an electrolyte is needed. Electrodes are the conductors of electricity that are in contact with the non-metallic part of the circuit (which in this case is the solution) (Bylikin & Horner, 2014). There are two types of electrodes: anode and cathode which are positively and negatively charged respectively.
Carefully scrape the excess powder from the top of the vessel as described for Method 2. Determine the mass (m0) of the powder to the nearest 0.1 per cent by subtraction of the previously determined mass of the empty measuring vessel. Calculate the bulk density (g/mL) by the formula m0/100 and record the average of 3 determinations using 3 different powder samples. 188.8.131.52 Method 3 Various samples of activated carbon with known weight will be wrapped in a plastic bag. And 400ml of water measured into the measuring cylinder.