Chapter 3 Matter Chapter 3 Table of Contents 3.1 3.2 3.3 3.4 3.5 Matter Physical and Chemical Properties and Changes Elements and Compounds Mixtures and Pure Substances Separation of Mixtures Return to TOC Section 3.1 Matter Matter • • Anything occupying space and having mass. Matter exists in three states. Solid Liquid Gas Return to TOC Section 3.1 Matter The Three States of Water Return to TOC Section 3.1 Matter Solid • • • Rigid Has a fixed volume and shape. Examples: Ice cube, diamond, iron bar Return to TOC Section 3.1 Matter Liquid • • • Has a definite volume but no specific shape. Assumes shape of container. Examples: Gasoline, water, alcohol, blood Return to TOC Section 3.1 Matter Liquid Water Takes the Shape of Its Container Return to TOC Section 3.1 Matter Gas • • • Has no fixed volume or shape. Takes the shape and volume of its container. Examples: Air, helium, natural gas, oxygen Return to TOC Section 3.2 Physical and Chemical Properties and Changes Physical Properties • • • The characteristics of matter that can be changed without changing its composition or doesn’t involve changing its composition. It’s an adjective. Characteristics that are directly observable. Examples: Odor, color, volume, state (s, l, or g), density, melting point, and boiling point Return to TOC Section 3.2 Physical and Chemical Properties and Changes Chemical Properties • • A substance’s ability to form new substances. The characteristics that determine how the composition of matter changes as a result of contact with other matter or the influence of energy. It’s an adjective. • Characteristics that describe the behavior of matter. • Examples: Flammability, steel will rust, and Food will digest Return to TOC Section 3.2 Physical and Chemical Properties and Changes Concept Check Classify each of the following as a physical or chemical property. physical Ethyl alcohol will boil at 78°C physical Hardness of a diamond Sugar will ferment to form ethyl alcohol chemical Return to TOC Section 3.2 Physical and Chemical Properties and Changes Physical Change • Change in the form of a substance, not in its chemical composition. It’s a verb. • Example: Boiling or freezing water Return to TOC Section 3.2 Physical and Chemical Properties and Changes Chemical Change • A given substance becomes a new substance or substances with different properties and different composition. It’s a verb. • Example: Bunsen burner (methane reacts with oxygen to form carbon dioxide and water) Return to TOC Section 3.2 Physical and Chemical Properties and Changes Electrolysis of Water Burning of Wood Return to TOC Section 3.2 Physical and Chemical Properties and Changes Electrolysis of Water • Water decomposes to hydrogen and oxygen gases. Return to TOC Section 3.2 Physical and Chemical Properties and Changes Concept Check How many of the following are examples of a chemical change? Pulverizing (crushing) rock salt Burning of wood Dissolving of sugar in water Melting a popsicle on a warm summer day Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.2 1 Physical and Chemical Properties and Changes Separate by Chemical Processes -burning -fermentation -rusting Matter Pure Substances Elements (atoms) Hydrogen Oxygen Copper Zinc Separate by Physical Processes -filtering -distillation -centrifuging Compounds (molecules) Water Alcohol Sugar Salt Mixtures Homogeneous (solutions) Air Sodas Ocean Water Alcoholic drinks Heterogeneous (most things) Granite Sand Wood Orange Juice Return to TOC Section 3.2 Physical and Chemical Properties and Changes Concept Check Classify each of the following as a physical or chemical change. Sugar fermenting to form ethyl alcohol chemical Iron metal melting physical Iron combining with oxygen to form rust chemical Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.3 Elements and Compounds Element • A substance that cannot be broken down into other substances by chemical methods. • Examples: Iron (Fe), aluminum (Al), oxygen (O2), and hydrogen (H2) • All of the matter in the world around us contains elements. Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.4 Mixtures and Pure Substances Pure Substances • Always have the same composition and are formed by chemical processes. • Either elements or compounds. • Examples: Pure water (H2O), carbon dioxide (CO2), hydrogen (H2), gold (Au) Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.3 Elements and Compounds Compound • A substance composed of a given combination of elements that can be broken down into those elements by chemical methods. • Examples: Water (H2O), carbon dioxide (CO2), table sugar (C12H22O11) • A compound always contains atoms of different elements. • A compound always has the same composition (same combination of atoms). Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.3 Elements and Compounds Concept Check How many of the following are compounds? H2O, N2, NaOH, MnO2, H2 Three – H2O, NaOH, MnO2 Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.4 Mixtures and Pure Substances Mixtures • • Have variable composition. Examples Wood, wine, coffee, granite • Can be separated into pure substances: elements and/or compounds using physical processes. Return to TOC Section 3.4 Mixtures and Pure Substances Homogeneous Mixture • • • • Same throughout. Having visibly indistinguishable parts. A solution. Does not vary in composition from one region to another. Apple Juice Cranberry Juice Orange Juice Return to TOC Section 3.4 Mixtures and Pure Substances Homogeneous Mixture – Examples • • • Air around you Brass Table salt stirred into water Return to TOC Section 3.4 Mixtures and Pure Substances Heterogeneous Mixture • • Having visibly distinguishable parts. Contains regions that have different properties from those of other regions. Return to TOC Section 3.4 Mixtures and Pure Substances Heterogeneous Mixture – Examples • • Oil and vinegar dressing Sand stirred into water Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.4 Mixtures and Pure Substances Concept Check Which of the following is a homogeneous mixture? Pure water Gasoline Jar of jelly beans Soil Copper metal Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.5 Separation of Mixtures • Mixtures can be separated based on different physical properties of the components. Different Physical Property Technique Boiling point Distillation State of matter (solid/liquid/gas) Adherence to a surface Chromatography Volatility Evaporation Filtration Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.5 Separation of Mixtures Distillation of a Solution Consisting of Salt Dissolved in Water Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.5 Separation of Mixtures • No chemical change occurs when salt water is distilled. Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.5 Separation of Mixtures The Organization of Matter Return to TOC Copyright © Cengage Learning. All rights reserved Section 3.5 Separation of Mixtures Filtration • Separates a liquid from a solid. Reverse Osmosis • Separates a liquid from a solution. See Chapter 15. Return to TOC Section 3.5 Separation of Mixtures Supercritical Carbon Dioxide Extraction Maxwell House decaffeinates its coffee using pure water and natural effervescence. (1978) See Chapter 15. SCF unit A method of making reduced oil content in food chip products, such as potato chips and corn chips, includes circulating liquid carbon dioxide, over the food chip products to extract oil. Reduction of oil content to less than 50% of its initial value, including reductions to 25%, may be achieved while retaining flavor and texture comparable to conventional deep fried chips having an oil content of 30% to 40%. The oil which is recovered from the liquid carbon dioxide used for extraction has an appearance and quality which are substantially the same as virgin frying oil and may be reused to deep fry chips. Return to TOC