Chapter #6 Properties of Matter Matter anything that occupies space and has mass. Pure Substance is matter with fixed composition, can be an element or a compound. Element a type of atom. About 90 are found in nature. All matter is made from element(s). Examples: He, Na, S Compound a pure substance consisting of two or more elements bonded together in fixed proportions. Examples: NaCl, H 2 O, CO 2 Sep 14 9:29 PM Mixture a combination of two or more different substances in such a way that no chemical reaction occurs. A mixture can usually be separated back into its original components. Heterogeneous mixture consists of visibly different substances or phases. Homogeneous mixture has the same uniform appearance and composition throughout. Many homogeneous mixtures are commonly referred to as solutions. Jan 26 11:07 AM 1
Element, Compound, or Mixture? Seawater Steel Copper Marble Iron oxide Diamond 14K gold Carbon dioxide Common Solutions: Gas + Gas = Liquid + Gas = Gas + Liquid = Liquid + Liquid = Liquid + Solid = Solid + Solid = Sep 14 9:30 PM Colloid is a heterogeneous mixture with intermediate particle size. Colloid particles may be seen in a beam of light such as dust in air in a "shaft" of sunlight. (Milk, fog, and jello are examples of colloids). Suspension is a heterogeneous mixture of larger particles. These particles are visible and will settle out on standing. (fine sand or silt in water or tomato juice). Oct 7 2:32 PM 2
The light beam is not visible as it passes through a true solution (left), but it is readily visible as it passes through colloidal iron (III) oxide in water. Shake well!! Oct 7 2:38 PM Physical Properties can be observed or measured without changing the composition of matter. Physical properties are used to observe and describe matter. Chemical properties of matter describes its "potential" to undergo some chemical change or reaction by virtue of its composition. Physical or Chemical Property? 1. Color 2. Density 3. Flammability 4. Boiling, or Melting points 5. Biodegradability 6. Rusting 7. Texture 8. Sublimation 9. Odor 10. Solubility Oct 17 8:11 PM 3
Physical Changes: A physical change takes place without any changes in molecular composition. The same element or compound is present before and after the change. The same molecule is present through out the changes. Examples: melting, freezing, boiling, evaporating, sublimation, and deposition, Physical Props/Changes Sep 14 9:38 PM A Chemical Change alters the composition of the original matter. Different elements or compounds are present at the end of the chemical change. The atoms in compounds are rearranged to make new and different compounds. Chem. Change For example hydrogen has the potential to ignite and explode given the right conditions. This is a chemical property. Sep 14 9:39 PM 4
Magnesium reacts with oxygen from the air producing an extremely bright flame. This is a chemical change since magnesium oxide has completely different properties than magnesium metal shown on the left. Jan 26 11:28 AM Steel wool is burning in a fast reaction with oxygen as contrasted with the slow rusting of iron also with oxygen. Oct 17 9:54 AM 5
Alka Seltzer reaction a solid tablet is dropped into water. Gas bubbles are observed. A chemical reaction occurred. A flaming or glowing splint is used to test for the gas. Oct 17 9:56 AM Sure Signs of Chemical Change Heat Light Gas Production (not from boiling) Precipitate a solid formed by mixing two liquids together. Physical or Chemical Change? 1. Water is heated in a microwave 2. Water boils 3. Water freezes into ice 4. Rust forms on an Iron Nail 5. A gas is compressed with a pump 6. A lump of coal burns 7. Table salt dissolve in water 8. Fermentation of grapes 9. Glass cup shatters 10. Butter burns in a frying pan Oct 17 9:59 AM 6
Qualitative Data Deals with descriptions. Data can be observed but not measured. Colors, textures, smells, tastes, appearance, beauty, etc. Qualitative Quality Quantitative Data Deals with numbers. Data which can be measured. Length, height, area, volume, weight, speed, time, temperature, humidity, sound levels, cost, members, ages, etc. Quantitative Quantity Qualitative data: friendly demeanors civic minded environmentalists positive school spirit Example: Freshman Class Quantitative data: 672 students 394 girls, 278 boys 68% on honor roll 150 students accelerated in mathematics Feb 1 12:34 PM Separation Methods Mixtures can be separated into their pure components by using physical methods. Separation techniques are physical methods used for the separation. We chose a technique based on the physical properties (such as B.P, F.P, solubility) of the components. For a sulfur iron mixture Use a Magnet Sep 14 9:38 PM 7
Ch. 6 Matter & Separtion.notebook Filtration is a mechanical or physical operation which is used for the separation of solids from fluids with the use of a filter. Filtration is done by passing a mixture through a filter. The residue is the substance that remains on the filter paper. The filtrate is the substance that flows through the filter paper. Oct 17 1:00 PM Evaporation this method is used for the separation of a soluble solid (solute) from its solvent. When the solution is heated the liquid solvent evaporates, leaving the dry solid solute behind. Oct 17 1:09 PM 8
Paper Chromatography The mixture (in this case two green ink spots) is put on a filter paper which is placed in a suitable solvent. This methods is based on the physical property of solubility. Jan 26 11:44 AM Distillation is a process of boiling a liquid, condensing and collecting the vapor. The purpose of distillation is purification or separation of the components of a mixture. This is separation is possible because the different boiling points of the components of the mixture. Fractional Distillation This is a special type of distillation used to separate a solution of two liquids. It can only work with liquids with different boiling points. Oct 17 10:07 AM 9
Crystallization is a process that produces pure solid crystals of a substance from a solution that contained the dissolved substance 1. Mix salts with solute, 2. heat the solution to dissolve the salts, 3. filter the solution, 4. solid crystals 'grows' out of the solution because the solution is too concentrated for all the solid to remain dissolved at that temperature. Oct 17 10:07 AM Chemical Separation Technique Electrolysis is a method of separating chemically bonded elements and compounds by passing an electric current through them. Electrolysis of copper(ii) sulfate solution with graphite electrodes Oct 17 1:25 PM 10
Separation Methods Which method should be used to separate the following mixtures? 1. Water and sand 2. Water and ethanol (alcohol) 3. Water and sodium chloride 4. Water and fuel oil 5. Copper and chlorine in copper chloride 6. Sugar and salt 7. Sugar and finely crushed glass 8. Dyes in water soluble ink Oct 19 9:55 PM Solubility Curves of Salts in Water Oct 19 9:54 PM 11
Looking at the solubility diagram, we deduce that at 50ºC, a maximum of about g of KNO 3 will dissolve in 100 g of water. If 120 g K 2 CO 3 are placed in 100 g of water, and the mixture heated to ºC, all the salt will dissolve. KNO 3 and K 2 CO 3 have the same solubility rate at ºC. 50 g of Pb(NO 3 ) 2 will dissolve in 100 g of water at ºC. The substance for which solubility is not much affected by temperature is. The substance with the highest solubility at 0ºC is. The lowest. Mar 2 10:59 AM Unsaturated Solutions If the amount of solute dissolved is less than the maximum that could be dissolved. Saturated Solutions The solution holds the maximum amount of solute per amount of the solvent. Supersaturated solution Solution that contain more solute than the maximum amount per solvent amount. Oct 31 12:52 PM 12
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