4. elements, compounds, mixtures and colloids


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4. elements, compounds, mixtures and colloids

  1. 1. Technological Institute of the Philippines 938 Aurora Blvd., Quezon City Experiment no. 4 Elements, Compounds, Mixtures and Colloids Submitted By: Group No.2 of Section ES11FB4 MEMBERS TASK PERFORMANCE TIME IN TIME OUT LAB GOWN (X/√) SIGNATURES OF MEMBERS Davis Banoog 1:30 4:30 Jenny-Ann Cabrera 1:30 4:30 Luis Miguel Benitez 1:30 4:30 Date Performed: July 19, 2013 Date Submitted: July 27, 2013 Engr. Renato Agustin Professor
  2. 2. OBJECTIVES: 1.1To identify and differentiate the fundamental characteristics of pure substances, mixture and colloids. APPARATUS AND MATERIALS: THEORY: Matter is composed of atoms that exist as solid, liquid or gas. It is classified into two, pure substance whose molecules are made up of one kind of atom while compounds are substances whose molecules are made up of two or more kinds of atoms combined in a definite proportion. An element cannot e transformed into simpler substances, while compound may be resolved into its elements; mixtures can be homogenous or heterogeneous. Homogenous mixture has no distinguishing characteristics when seen by the naked eye. For heterogeneous mixture, the substance still carries their identity when they are mixed and displays more than one phase marked off by visible boundaries. Colloid is a heterogeneous mixture of two or more substances in which their finely subdivision molecules remain suspended in the dispersion medium for a considerable length of time. Colloid possesses Tyndall Effect which is a property to scatter light in all directions. 1 10 ml Graduated Cylinder 1 Magnet 4 Test Tube 1 Test tube Rack 1 Test tube Holder 1 Test tube Brush 1 Triple Beam Balance 2 Watch Glass 1 25 ml Beaker 1 50 ml Beaker 1 Penlight 1 Stirring Rod Sulfur Water NaCl Crystal Cooking Oil Starch Solution Sugar Solution Dishwashing Liquid Iron Filings
  3. 3. PROCEDURE: 1. Element 1.1 Place 0.5 grams of sulfur in a watch glass. Observe its color, odor and state. 1.2 Get a bar magnet and draw it near the sulfur. Record your observation. 1.3 Place a pinch of sulfur in a test tube and add 5 ml of water. Shake it thoroughly. Does the sulfur dissolved in water? Is it completely soluble, partially soluble or insoluble? 1.4 Place 0.5 grams of iron fillings on a watch glass. Observe its color, odor and state. 1.5 Get a bar magnet and draw it near the iron filings. Record your observation 1.6 Place 0.5 grams iron filings in a test tube and add 5 ml of water. Shake it thoroughly. Does the iron filings dissolved in water? 1.7 Mix thoroughly the sulfur and iron filings in a watch glass. Can you identify iron and sulfur separately? 1.8 Run a magnet through the mixture. What did you observe? 2. Mixture 2.1 Weigh 0.5 grams of NaCl crystals. Observe its color, odor and state. Test the magnetic property of NaCl crystals. Record your observation. 2.2 Measure 5 ml of water in graduate cylinder and place in a test tube. Dissolve the 0.5 grams of NaCl in the water. Can you distinguish the NaCl crystals in the mixture? What do you call the mixture? 2.3 Measure 5 ml of cooking oil. Observe its color, odor and state. Test the magnetic property of cooking oil. Record your observation. Place 5 ml of water in another test tube and add the 5ml of cooking oil. 2.4 Shake gently. Can you distinguish the cooking oil from the water in the mixture? Record your observation. 3. Colloid (Tyndall Effect) 3.1 Place a beaker containing water against a beam of light. 3.2 Observe by viewing the beaker at the right angle to the beam of light. Is the light scattered or did it pass through water? 3.3 Repeat by using 2% starch, soap and sugar solution. Record your observations?
  4. 4. OBSERVATION: Elements Any substance that contains only one kind of an atom is known as an element. Because atoms cannot be created or destroyed in a chemical reaction, elements such as sulfur (S8) cannot be broken down into simpler substances by these reactions. Compounds It is consists of atoms of two or more different elements bound together. Compounds can be broken down into a simpler type of matter (elements) by chemical means (but not by physical means) and always contains the same ratio of its component atoms. Mixtures A mixture is made from molecules of elements and compounds that are simply mixed together, without chemical bonds. Mixtures can be separated using techniques such as filtration, evaporation and distillation.
  5. 5. DATA AND RESULTS: SUBSTANCE PHYSICAL STATE COLOR ODOR MAGNETIC PROPERTY SOLUBILITY IN WATER OBSERVATION Sulfur solid yellow green unpleasant not attracted insoluble S + Fe not mixedIron Filings solid black odorless attracted insoluble NaCl Crystal solid white odorless not attracted slightly soluble NaCl + water slightly soluble Cooking Oil liquid yellowish unpleasant not attracted insoluble Cooking oil + water not mixed SUBSTANCE CLASSIFICATION (Element, Compound, Colloid, Solution) Sulfur Element Iron Filings Element Sulfur + Iron Filings Compound NaCl Compound NaCl + water Solution Cooking oil Colloid Cooking oil + water Solution Starch Solution Colloid Soap Solution Colloid Sugar Solution Colloid MIXTURE OBSERVATION (Tyndall Effect) Water the light passed through Starch Solution light scattered Soap Solution the light passed through Sugar Solution light scattered
  7. 7. Figure 1 Figure 2. Testing the magnetic property. Figure 3. Solubility. Iron Filings Sulfur NaCl Iron Filings Sulfur NaCl Procedure no. 1.5 Procedure no. 1.2 Procedure no. 2.1 Iron Filings + H2O NaCl + H2O Sulfur + H2O Cooking oil + H2O Procedure no. 1.6 Procedure no. 2.2 Procedure no. 1.3 Procedure no. 2.3
  8. 8. Figure 4. Tyndall Effect water starch solution soap solution sugar solution
  10. 10. QUESTION AND ANSWER: 1. Did the addition of sulfur with iron filings produce a new compound? Why? The difference between mixtures and compounds is that mixtures can be separated again by physical means. Compounds must be separated by chemical means. This is an indication that the atoms in a mixture are not holding onto each other, they just happen to be nearby. In a compound, the atoms of the constituent substances are connected atom-to-atom by chemical bonds. Chemical bonds are where the atoms either share electrons between them (valence bonds), or exchange electrons, and are then attracted to each other by electrostatic forces (ionic bonds). You can mix iron powder and sulfur together, and separate it out again by using a magnet. 2. How did the mixture of sulfur and iron filings respond to the magnet? The iron filings are attracted by the magnet because of its property making the particles of iron filings separated from the sulfur. 3. How many phases do you observe when you add NaCl crystal in water? We observed that when we add NaCl crystals in the water it has 2 phases: soluble and the non soluble. 4. What is Tyndall Effect? The Tyndall effect is the scattering of light as a light beam passes through a colloid. The individual suspension particles scatter and reflect light, making the beam visible. The amount of scattering depends on the frequency of the light and density of the particles.