EXPERIMENT NO. 1 CHARACTERISTICS OF MATTER Elise Angela H. Espinosa Kyle Maxinne R. Romero Denmirson Vivo
TCD 4, Group # 1, Maam MJ Punzalan 07 January 2014
I. ABSTRACT This experiment was divided into three major parts: Part A – Physical Separation of the Components of a Mixture, Part B – Analysis of the Components of the Mixture, and Part C – Changes in the Components of the Mixture. Different data were gathered in this experiment. Substances were classified into metals and non-metals after the experiment had been performed. The difference between physical and chemical change had also been found out. Last, the differences of reactivity level between different substances were also observed in the experiment. Also, different laboratory techniques were used in order to obtain the results desired. II.
KEYWORDS: reactions, metals, non-metals, acidic, basic, components
III.
INTRODUCTION
Matter is anything that occupies space and has mass. It can be classified according to its composition. Samples of matter that have a definite composition are called pure substances. Pure substances can be either elements or compounds depending on the number of constituting particles. Mixtures, on the other hand, are samples of matter whose composition may vary according to preparation. These may be further classified into solutions, colloids, and suspensions based on particle size. The components of pure substances and mixtures can be separated through physical or mechanical methods for the latter and chemical techniques for the former. Matter can also be classified according to its properties. These properties are determined by its components’ individual properties, and may be physical or chemical. Metals, nonmetals and metalloids are classified based on their properties. The components of matter may also undergo physical or chemical changes. Chemical changes are those that cause chemical reactions that alter a substance’s chemical composition. The above principles were all considered and studied in Experiment 1 as it aimed to: (1) identify the different methods of separating components of a mixture; (2) apply the laboratory techniques needed for each method of separation; (3) differentiate metals from non-metals; (4) differentiate physical from chemical change; and (5) determine the relative reactivities of different elements. Fulfillment of these objectives led to a more detailed and better understanding of the characteristics of matter, on the part of the students. The objectives were achieved through the division of the experiment into three parts: Part A was focused on the different physical separation techniques, while Part B was focused on analyzing the components’ properties. Lastly, Part C was centered on the changes that the components underwent. IV.
METHODOLOGY
CHEM 14.1, Characteristics of Matter
For this experiment where different substances from a mixture were separated physically, analyzed and classified, several procedures had been performed. Part A: Physical Separation of the Components of a Mixture Iron (Fe) filings, ground mothballs and table salt were measured and their properties were observed. They were then mixed in an evaporating dish, together with two strips of Magnesium (Mg) ribbon and a pinch of food coloring. Afterwards, the mixed dry substances were scattered in a clean sheet of paper, and then a magnet was passed underneath the paper. The substances that weren’t magnetized were placed in a 50-mL beaker in order to be used for the next procedure. Thirty milliliters (30mL) of water was added to the 50-mL beaker and the mixture was mixed for a minute with a glass rod. The mixture was then filtered through the use of a filter paper, funnel and another beaker. The filtrate was saved while the residue was transferred into an evaporating dish. The set-up for the next procedure was prepared: a sheet of perforated filter paper was placed on top of the evaporating dish with the residue, and then an inverted funnel with a cotton plug in its tip was placed on top of the filter paper. The set-up was heated until there were deposits on the walls of the funnel. The filtrate saved was boiled and a pinch of activated charcoal was added. The boiling was continued until only 20-mL of the mixture remained. The mixture was filtered and the filtrate was saved in a test tube. An iodine (I2) crystal was added to 2mL of the filtrate in a test tube, and then the test tube was shook. Later on, 1mL of hexane was added. With a medicine dropper, the different layers were separated into two different evaporating dishes. These layers were evaporated under the fume hood. Part B. Analysis of the Components of the Mixture Small amounts of iron (Fe), magnesium (Mg), iodine (I2) and mothballs were placed in four separate test tubes. Afterwards, 10 drops of 0.1M hydrochloric acid (HCl) were added and the test tubes were immediately covered with stoppers. Evolution of gas was observed.
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A magnesium (Mg) ribbon was heated directly over a lit alcohol lamp until the ribbon burned. The ashes collected after the ribbon was heated were placed in a test tube. Afterwards, 5mL of water was added and then the test tube was shook. Observations were made. Using litmus papers, acidity or basicity was tested. The tip of a glass rod was heated over an alcohol lamp for a minute. On the heated tip, a sprinkle of sulfur powder was placed. The powdered tip was heated and then the rod was inserted into a test tube. Fumes were collected and then the test tube was covered with a stopper, afterwards. 1mL of water was added and then the acidity or basicity of the solution was tested. Part C. Changes of the Components of the Mixture A pinch of Fe, food coloring, table salt and two iodine crystals were placed separately into 20-mL test tubes. The test tubes were heated with low flame. The test tubes were cooled. Necessary observations were done. Small amounts of Fe and Mg were placed into two separate test tubes. Ten drops of 0.1M HCl were added to each test tube. Observations for chemical changes were done. Filtrate saved from Part A was placed in an evaporating dish and was tested with a red litmus paper. Afterwards, it was evaporated to dryness. V.
RESULTS
Part A. Physical Separation of the Components of a Mixture
Magnesium(Mg) ribbon, food color, table salt, activated charcoal Adsorption
Activated charcoal, food color, table salt
Activated charcoal
Sublimation
Magnesium(Mg) ribbon, mothballs
Magnesium (Mg) ribbon
Sublimation
Magnesium(Mg) ribbon, mothballs
Mothballs
Solvent extraction & evaporation
Food coloring (in aqueous layer), table salt (in hexane layer)
Food coloring
Solvent extraction & evaporation
Food coloring (in aqueous layer), table salt (in hexane layer)
Table salt
Table 2. Components isolated after each method of separation Part B. Analysis of the Components of the Mixture Table 3 shows the results when 0.1 M HCl was added to the substances. Reaction with 0.1 M HCl is useful in determining a substance’s metallic character. SUBSTANCE
In Table 1, the colors and textures of the substances used in the experimented are shown. SUBSTANCE
COLOR
TEXTURE
Iron (Fe) filings
black
Coarse; irregular
Mothballs
White
Fine; powder-like
Table Salt
White
Crystal-like
Mg ribbon
Silver
Smooth
Food color
orange
Fine
Table 1. Physical properties of substances In Table 2, the components, that are isolated from all the different substances in the mixture, in each method of separation are shown. METHOD OF SEPARATION
Magnetic separation
SUBSTANCES INVOLVED METHOD Iron(Fe) mothballs,
IN
filings,
SEPARATED COMPONENT IN EXPERIMENT Iron (Fe) filings
CHEM 14.1, Characteristics of Matter
Continuous evolution of gas (+/-)
CLASSIFICATION (metallic/nonmetallic)
Iron (Fe)
+
Metallic
Magnesium (Mg)
-
Non-metallic
Naphthalene Balls
-
Non-metallic
Iodine (I2)
-
Non-metallic
Table 3. Reaction of substances with 0.1M HCl Table 4 shows the reactions of the substances’ oxides and their observed alkalinity. ELEMENT
Observation w/ Litmus Paper
CLASSIFICATION (BASIC/ACIDIC)
Magnesiu m
no change
Neutral
Sulfur
no change
Neutral
Table 4. Reaction of elements with oxygen Table 5 shows the differences in chemical properties of metals and non-metals, based on the experimental results.
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SUBSTANCE
OBSERVATION
TYPE OF CHANGE
Fe filings
No physical change
None
Food color
Turned black; moistened walls of test tube
Chemical
I
Pink sublimation
Chemical
Both the mothballs and ribbons were solids, and sublimation separates solids by transforming one of the substances directly into gas form, skipping the liquid phase. The substance sublimated was the mothball component, which caused the vapor formed on the walls of the funnel. The remaining components on the evaporating dish were the Mg ribbons. On the mixture with charcoal and food coloring, adsorption was done. Adsorption is performed using activated carbon (which comprises activated charcoal), is usually used here because it is useful in attaining a large internal surface (500- 1500 m2/g). This process was used in separating the food coloring from the mixture. The next separation technique used was solvent extraction. This method employs two immiscible solvents to extract organic compounds from water soluble compounds. The solvents used in the experiment were iodine and hexane, labeled aqueous and hexane layers, respectively. Once the two layers were separated by a medicine dropper, evaporation was performed on both to separate the solid solute from the liquid solvent, which was the component evaporated. When evaporation was completed, the remaining solids were the food coloring and table salt from the aqueous and hexane layers, respectively.
NaCl
Popping sound; moistened walls of test tube
Chemical
Part B. Analysis of the Components of the Mixture
Mg ribbon
Fireworks-like sparks
Chemical
METAL
NON-METAL
Basic
Acidic
Produces gas evolution w/HCl
Does not produce gas evolution w/ HCl
Table 5. Chemical Properties of Metals vs. Non-Metals Part C. Changes of the Components of the Mixture Reaction to heat is a useful indicator of the type of change that occurs. Table 6 shows the observed results when the substances in the experiment were heated.
2
Table 6. Reactions of substances to heat Table 7 presents the reactions of substances with 0.1 M HCl compared to each other SUBSTANCE
TYPE OF CHANGE with 0.1M HCl
Iron (Fe) filings
Formation of bubbles (slower)
Mg ribbon
Formation of bubbles (faster)
Table 7. Reaction of substances with 0.1M HCl VI.
DISCUSSION
Part A. Physical Separation of the Components of a Mixture As mentioned in Part I, mixtures can be separated by physical means. The first method of separation employed in the experiment was the magnet. Magnets attract metals, which is why the iron (Fe) filings were separated from the rest of the mixture when the magnet passed across the sheet of paper they were in. The next method used was filtration. Filtration separates solids (that are not dissolved) from liquids by letting the liquid pass through the pores of the filtering substance. The liquid filtered is called the filtrate, while the remaining solid is the residue. This was the process that separated the mothballs and magnesium (Mg) ribbons from the charcoal and food coloring. Afterwards, the mixture containing the mothballs and Mg ribbons was heated in the process called sublimation.
CHEM 14.1, Characteristics of Matter
Acids react with metals to form a salt and hydrogen gas bubbles. This proves why both Fe and Mg should have exhibited continuous gas evolution when HCl was added to them. Possibly, the Mg ribbon used was contaminated or not cleaned properly, so it didn’t react to the acid as it should have. Acids do not react with nonmetals because nonmetals do not readily give their electrons. This makes sense of the absence of gas formation from the naphthalene balls and iodine when HCl was added to them. Based on the experiment, there were no changes observed on either blue or red litmus papers for the oxides of both magnesium and sulfur. However, magnesium oxide is known to be basic, while sulfur oxide is acidic. It is possible that the litmus, being paper, had already expired or was contaminated. It may also have been improperly stored or used. In summary, metals and nonmetals have opposing properties. Metals are reactive to acids, while nonmetals are not. Metal oxides are also basic, while nonmetal oxides are acidic. Part C. Changes of the Components of the Mixture As mentioned in the Introduction, matter may undergo physical and chemical changes. There are five indicators of a chemical change or reaction: color, gas formation, precipitation, odor, and temperature change. According to the results, the Mg ribbon, food color, and I2 crystals all experience chemical changes based on the gas formation and/or color changes they experienced. The experimental results for these substances are the same as the expected results. Deviations from the theoretical results
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were observed in the reaction of Fe and table salt. The iron, when heated, should have formed orange precipitates on the walls of the test tube, while it was table salt that should have been unreactive. These deviations may be, again, caused by contamination or impurities. As for the reactions of Fe and Mg with HCl, both additions resulted in gas formation. The bubbles formed faster for Mg, though, indicating that Mg was the more reactive metal.
uncontaminated. This is to ensure that the results being obtained are going to accurate.
VII.
Silberberg, M.S. (2006). Chemistry: The molecular nature of matter and change. (5th ed.). New York, NY: McGraw-Hill Companies, Inc.
GUIDE QUESTIONS AND ANSWERS
Part B. Analysis of the Components of the Mixture 1. Among those classified as metals, which is the most reactive with 0.1 M HCl? Iron (only one substance was classified as a metal; but should be Magnesium as discussed in the discussion part of this report) 2. Completed and balanced reactions: a. MgO (s) + H2O Mg(OH)2 b.
SO2 + H2O
H2SO3
IX.
REFERENCES
Brown, T.L., LeMay, H.E.J., Bursten, B.E., Murphy, C.J., & Woodward, P.M. (2012). Chemistry: The central science. (12th ed.). Glenview, IL: Pearson Education, Inc.
Lenntech. (n.d.). Filtration. Retrieved from http://www.lenntech.com/chemistry/filtration.htm Lenntech. (n.d.). Adsorption. Retrieved from http://www.lenntech.com/library/adsorption/adsorptio n.htm#ixzz2oxYpS2Wr Lal, S. (2010). Matter – 02: Separation of mixtures. Retrieved from http://www.mentorials.com/high-schoolchemistry-matter-separation-of-mixtures.htm
Part C. Changes of the Components of the Mixture 1. Based on the reaction in Table 7, which is the more active metal? Magnesium 2. What is the composition of the filtrate in A-3b? Water & salt 3. Completed and balanced reactions: a. 2Fe + 6HCl 2FeCl3 + 3H2
VIII.
b.
Mg + 2HCl MgCl2 + H2
c.
3Mg + 2FeCl3 3MgCl2 + 2Fe
The Interactive Lab Primer. (n.d.). Solvent extraction. Retrieved from http://www.chemilp.net/labTechniques/SolventExtraction.htm Boundless. (n.d.). Gas evolution reactions. Retrieved from https://www.boundless.com/chemistry/aqueousreactions/acid-base-reactions/gas-evolutionreactions/ Bodner Research Web. (n.d.). Oxidation-reduction reactions. Retrieved from http://chemed.chem.purdue.edu/genchem/topicrevie w/bp/ch19/oxred_1.php
CONCLUSIONS AND RECOMMENDATIONS
Based from all the procedures performed, results obtained, and information gathered from external sources by the researchers, the following can be inferred: 1. Physical changes occur when only the phase of the substance is changed. On the other hand, chemical changes occur after undergoing chemical reactions. 2. Metals oxides are basic; Non-metal oxides are acidic. 3. Metals form gas evolution with an acid, while nonmetals do not form gas evolution when mixed with an acid. 4. Different metals have different reactivity levels. The researchers highly recommend the next performers of this experiment to make sure that all substances, equipment and materials used are clean and
CHEM 14.1, Characteristics of Matter
I hereby certify that I have given substantial contribution to this report.
Elise Angela H. Espinosa
Kyle Maxinne R. Romero
Denmirson Vivo
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