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Elements, Compounds, and Mixtures

Elements, Compounds, and Mixtures. Chapter 4 Material on Midterm. Mystery Mixture. What colors make up black ink?. Section 1: Elements. Objectives Describe pure substances Describe the characteristics of elements, and give examples Explain how elements can be identified

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Elements, Compounds, and Mixtures

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  1. Elements, Compounds, and Mixtures Chapter 4 Material on Midterm

  2. Mystery Mixture • What colors make up black ink?

  3. Section 1: Elements • Objectives • Describe pure substances • Describe the characteristics of elements, and give examples • Explain how elements can be identified • Classify elements according to their properties

  4. Section 1: Elements • The simplest substance? An element! • An _____________ is a pure substance that cannot be separated into simpler substances by physical or chemical means • A ___________________________is a substance in which there is only one type of particle • Called ___________ element Pure substance atoms

  5. Section 1: Elements • Properties of Elements • Identified by their characteristic properties • Do not depend on the ______________ of a substance • Boiling point • Melting point • Density • Reactivity • No two elements have the same atoms • May need more than one property to identify amount

  6. Elements • They are listed on the Periodic Table of Elements. • Each element can be identified by its physical properties and chemical properties. • Most elements are solidsat room temperature (20°C). • 11 are gases. • 2 are liquids. • All elements are represented by universallyrecognized symbols

  7. Section 1: Elements

  8. Classifying Elements • Example: Dog Breeds How do you tell one breed from the other? • Three categories of elements. • Elements are organized on the Periodic Table by similar properties.

  9. Section 1: Elements • Classifying Elements by their Properties • Three main categories • _______________are elements that are shiny and good conductors of heat and electricity • _________________ are elements that conduct heat and electricity poorly • ___________________ are elements that have both properties of metals and nonmetals Metals Nonmetals Metalloids

  10. Section 1: Elements

  11. Section 1: Elements • Section Review • Please answer the objectives on your summary sheet • Describe pure substances • Describe the characteristics of elements, and give examples • Explain how elements can be identified • Classify elements according to their properties

  12. Section 2: Compounds • Objectives • Explain how elements make up compounds • Describe the properties of compounds • Explain how a compound can be broken down into its elements • Give examples of common compounds

  13. Section 2: Compounds • What are compounds? • A compound is a pure substance composed of two or more elements that are ______________combined • As a result of a ______________ chemically reaction

  14. Compounds • Compounds – • a substance made up of atoms of twoor more elements chemically combined by chemical bonds. • When elements combine, they chemically react and undergo a chemical change.

  15. Section 2: Compounds Sodium chloride Water Carbon dioxide

  16. Section 2: Compounds • The Ratio of Elements in a compound • A compound is a pure substance • The ratios in a compound are ALWAYS THE ________ • EX: Water is ____________ • The water to oxygen mass has a ratio of 1: 8 • Same in 1 drop to 100 gallons • Different ratio? _________________! SAME H2O NOT WATER

  17. Section 2: Compounds • Properties of Compounds • Compounds have their _______ physical and chemical properties • EX: melting point, density, color • Physical or chemical? • EX: reactivity, flammability • Physical or chemical? OWN

  18. Section 2: Compounds • Properties Compounds versus Elements • A compound will have different ______________ than the elements that make it up properties

  19. Compounds Chlorine • Gas • Poisonous • Greenish-yellow Sodium Soft Silvery, white metal Reacts violently with

  20. But when chemically combined… NaCl = Table salt! You get……..

  21. Section 2: Compounds • Breaking Down Compounds • Compounds can _____________________ into • Smaller compounds • Elements • Must be done by a _______________ change • Add heat energy • Add electric energy break down chemical

  22. How to break down a compound • The only way to break down a compound is through a chemical change. • Energy is needed for a chemical change to happen. • 2 ways to add energy to break a compound • 1. apply heat • 2. apply an electrical current

  23. Section 2: Compounds • Section Review • Please answer the objectives on your summary sheet • Explain how elements make up compounds • Describe the properties of compounds • Explain how a compound can be broken down into its elements • Give examples of common compounds

  24. Section 3: Mixtures • Objectives • Describe three properties of mixtures • Describe methods of separating the parts of a mixture • Analyze a solution in terms of its solute and solvent • Describe factors that affect solubility for solids, liquids, and gases • Explain how concentration affects a solution • Describe the particles in a solution, suspension, and colloid • Explain the difference between colloids, solutions, and suspensions

  25. Section 3: Mixtures • What is a mixture? • A mixture is a combination of two or more substances that are _______________________________ • No chemical reaction • No compound formed • Each substance keeps its original ______________ • Examples: pizza, sugar water, Italian dressing, sand, concrete not chemically combined identity

  26. 2 Categories of Mixtures • a type of mixture in which the parts of the mixture are noticeably different from one another. • Ex. Trail mix, pizza, Italian dressing • a type of mixture in which the substances are so evenly distributed that it is difficult to distinguish one substance in the mixture from another. • Ex. Sugar water, concrete Heterogeneous Mixture Homogeneous mixture

  27. Section 3: Mixtures • Separating mixtures • Use _____________ means • Can take more than one step physical

  28. Section 3: Mixtures

  29. Separating a mixture Distillation – a process that separatessubstances in a solution by using their boiling points. Magnetism can be used to separate magnetic substances (Iron, Cobalt, and Nickel) from non-magnetic substances.

  30. Separating a mixture • Filtration - a process to separatematerials based on their size. Ex: coffeefiltersand a screen to find artifacts at a historical site. • A Centrifuge can separatesubstances based of their densities. • Densermaterials separate first.

  31. Section 3: Mixtures • The Ratio of Components in a Mixture • No fixed ratio—______ always the same not

  32. Section 3: Mixtures • Comparing Mixtures and Compounds elements both No change Change chemical physical any set

  33. Section 3: Mixtures • What is a solution • A solution is a mixture that appears to be a single substance • ____________ be filtered, cannot scatter light • Who is who? • The ______________ is the substance that is dissolved • The _____________ is the substance in which the solute is dissolved Cannot solute solvent

  34. Section 3: Mixtures Hide the LOOT in the VENT!

  35. Section 3: Mixtures • Solutions form when the solute dissolves in the solvent • If it ________ dissolve, its soluble • If it _____________ dissolve, it is insoluble does doesn’t

  36. Section 3: Mixtures

  37. Section 3: Mixtures • Concentration of Solutions • The concentration is a measure of the __________ of solute in a solvent • Units: g/mL • Lots of solute  __________________ • Little solute _______________ amount concentrated dilute

  38. Section 3: Mixtures • What is solubility? • The solubility is the ability of a solute to ____________ in a solvent at a certain temperature dissolve

  39. Section 3: Mixtures • How does temperature affect solubility? • For liquid solvents • A higher temperature makes a gas _______ soluble • A higher temperature makes a solid _______ soluble • USUALLY • A higher temperature makes a liquid more soluble less more

  40. Section 3: Mixtures • To get solids to dissolve faster… Mix, stir, or shake Heat Crush

  41. Section 3: Mixtures • What is a suspension? • A suspension is a mixture in which particles are large enough to be dispersed, but they settle out over time • Can be _______________, can scatter __________ filtered light

  42. Suspension A heterogeneous mixture that separatesinto layers after time. • Need to be stirred or shaken. • Ex. Italian dressing, snow globe, muddy water

  43. Section 3: Mixtures • What is a colloid? • A colloid is a mixture in which the particles are dispersed throughout but are not heavy enough to settle out • ___________ be filtered, _______ scatter light Cannot can

  44. Colloid - Form a homogeneousmixture. • Ex. Milk, mayo, gelatin, whipped cream, stick of deodorant

  45. No Yes Yes No Yes No

  46. Section 3: Mixtures • Section Review • Please answer the objectives on your summary sheet • Describe three properties of mixtures • Describe methods of separating the parts of a mixture • Analyze a solution in terms of its solute and solvent • Describe factors that affect solubility for solids, liquids, and gases • Explain how concentration affects a solution • Describe the particles in a solution, suspension, and colloid • Explain the difference between colloids, solutions, and suspensions

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