The lab questions provided are answered below:
1) There are many clues that indicate whether a chemical reaction has occurred. These include: a colour change, a gas being formed, a solid being formed, a change in temperature, precipitates are formed, a change in smell, light being emitted, a change in mass or volume, a change in conductivity, a change in boiling and/or melting point, and a change in taste. In the chart above, the “How do we know a reaction occurred?” column lists clues as to how it was known that a reaction occurred.
3) A participate is a solid that cannot be dissolved and was materialized from a liquid solution. The first precipitate that we came across was was in reaction 6. This reaction included sodium chloride and silver nitrate. Once the sodium chloride was poured into the silver nitrate, a precipitate was formed. This precipitate was silver chloride (AgCl) and is yellow in colour. The second precipitate that was found was in reaction 7. This reaction involved lead (II) nitrate being poured into potassium iodide. This reaction formed lead (II) iodide which is a precipitate as well.
…show more content…
They would need to hold this splint into a test tube that they want to test for O2. If the test tube includes O2, the splint will reignite. This test is called a glowing splint test. To test for CO2, one would need a test tube with limewater(calcium hydroxide). One would then bubble CO2 into the solution and CO2 is present, the limewater would become cloudy and foggy. This test is called the limewater test. Finally, to test the presence of H2, one would need a flaming splint. They would hold the flaming splint into the test tube that they want to test for hydrogen. If a pop is heard, H2 is present. This test is called the pop test. O2 was released in reactions 8 and 9. H2 was released in reactions 1, 3, 4, and
When the flame was blown out and the glowing wooden splint was placed halfway into the test tube containing H2O2 and MnO2 crystals, the splint reignited and caught flame once again. This demonstrates the decomposition of H2O2 into water and hydrogen. MnO2 is a catalyst that increases the rate at which H2O2 decomposes. Adding oxygen to a fire will cause it to burn faster and hotter and the oxygen rich test tube allowed the splint to reignite.
Cu (aq) + 2NO3 (aq) + 2Na+ (aq) + 2OH- (aq) → Cu(OH)2 (s) + 2Na+ (aq) + 2NO3(aq)
The fifth experiment of the semester entails a synthesis reaction geared towards analyzing the structure of a product. The starting material is isopentyl alcohol. When reacted with acetic acid with sulfuric acid as a solvent, isopentyl alcohol produces isopentyl acetate, which is the goal product, as shown in the reaction below:
Moreover, another purpose was to learn how to use different lab techniques, such as filtration and proper heating of test tubes, in order to determine the mass of products produced by the reaction. Not only that, the experiment demonstrates how transition elements can often form more than one type of reaction due to their differently charged ions, like Fe.
Purpose/Introduction: In this experiment, four elimination reactions were compared and contrasted under acidic (H2SO4) and basic (KOC(CO3)3) conditions. Acid-catalyzed dehydration was done on 2-butanol and 1-butanol; a 2o and 1o alcohol, respectively. The base-induced dehydrobromination was performed on 2-bromobutane and 1-bromobutane isomeric halides. The stereochemistry and regiochemistry of the four reactions were analyzed by gas chromatography (GC) to determine product distribution (assuming that the amount of each product in the gas mixture is proportional to the area under its complementary GC peak).
Cations are positively charged ions, which are attracted to their negatively charged counterparts, anions. Precipitates can form when these cations and anions combine in aqueous solutions; however, precipitates only form if one of the products of the chemical reaction is not soluble in that solution. Solubility is instrumental in understanding how precipitation reactions occur. This is because solubility rules, determine whether a precipitate can form. A precipitate can form if the cation in the compound is soluble when combined with an anion. For example when the solutions silver nitrate and sodium chloride (reactants) are mixed, silver chloride and sodium nitrate (products) are formed. Following the solubility laws, silver nitrate is the precipitate, as it isn’t
The purpose of this lab is to determine the empirical formula of copper oxide (CuxOy) through a single-displacement reaction that extracts the copper (Cu) from the original compound. In order to do this, hydrochloric acid (HCl) was mixed in with solid CuxOy; the mixture was stirred until the CuxOy was totally dissolved in the solvent. Zinc (Zn) was then added to the solution as a way to enact a single displacement reaction in which Cu begin to form on the Zn; the Cu gets knocked off the Zn through gentle stirring. To isolate the Cu, the supernatant liquid was decanted and the Cu was then washed with first water then second, isopropyl alcohol. Once done, the hydrated Cu is transferred onto an evaporating dish where it was heated multiple times
Classes of Chemical Reactions Whenever a reaction takes place, energy is changed as well when the substances react chemically. Scientists have taken these changes in energy and generalized them. Scientists can take these generalizations and discover more about the nature and tendencies of matter. In this lab, the purpose was to perform seven reactions, write down their equations, and identify the type of reaction.
During our lab we found our mass percentages for our sample to consist of 20.5% of NH4CL, 48.5% of NaCl, and 25.6% of SiO2. Being that the actual percentages of our mixture were 20% of NH4CL, 50% of NaCl, and 30% of SiO2. After using the percent error equation that was provided to us in class we found there to be a 5.4% error which is relatively accurate.
Chemical kinetics is a branch of chemistry that involves reaction rates and the steps that follow in. It tells you how fast a reaction can happen and the steps it takes to make complete the reaction (2). An application of chemical kinetics in everyday life is the mechanics of popcorn. The rate it pops depends on how much water is in a kernel. The more water it has the quicker the steam heats up and causes a reaction- the popping of the kernel (3). Catalysts, temperature, and concentration can cause variations in kinetics (4).
In this lab experiment, around 5 grams of hydrogen peroxide went through a chemical reaction with potassium iodide, producing oxygen gas and water vapor. After three trials of the experiment concluded, Dalton’s law of partial pressure and the ideal gas law was used to determine the number of moles of oxygen produced and the percent hydrogen peroxide in an aqueous solution. The average number of moles of oxygen produced within the experiment was 0.002537 mol. O2 and the average mass percent of hydrogen peroxide was calculated as 3.434%. The mass percent of hydrogen peroxide was slightly over the accepted amount of 3%, indicating that some tiny errors had occurred during the experiment.
Investigationg of Chemical and Physical Changes Why I am conducting this experiment? In order to learn how to recognize chemical and physical changes, I have to carry out this experiment to see different chemical and physical changes of different substance. How can we recognize physical changes and chemical changes? -----------------------------------------------------------
is impossible to specify a single best method to carry out a given analysis in
borate) and 1.0 g. of sodium hydroxide in 20 mL of warm water. It may