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Words to Study for Chem. Test

Words to Study for Chem. Test. Solid Liquid Gas/Gas Laws Change of State Melting/Melting Point Boiling/Boiling Point Freezing/Freezing Point Evaporation Condensation Sublimation Endo/Exothermic. Mass Weight Matter Physical Properties Chemical Properties Characteristic Properties

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Words to Study for Chem. Test

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  1. Words to Study for Chem. Test • Solid • Liquid • Gas/Gas Laws • Change of State • Melting/Melting Point • Boiling/Boiling Point • Freezing/Freezing Point • Evaporation • Condensation • Sublimation • Endo/Exothermic • Mass • Weight • Matter • Physical Properties • Chemical Properties • Characteristic Properties • Physical Changes • Chemical Changes • Signs of Chem. Change • States of Matter • Atoms

  2. Words to Study for Chem. Test • Chemical Formulas • Chemical Equations • Reactants • Products • Subscripts • Coefficients • Law of Conservation of Mass • Decomposition Reaction • Replacement Reaction • Synthesis Reaction • Solution • Solubility • Suspensions • Colloids • Pure Substance • Element • Compound • Mixture • Homogeneous Mixture • Heterogeneous Mixture

  3. Chemical Formulas • A combination of chemical symbols and numbers to represent a substance • Examples • H20: Water • CO2: Carbon Dioxide • NaCl: Salt • C6H1206: Sugar

  4. Chemical Equations • A representation of a chemical reaction that uses symbols to show the relationship between the reactants and the products • Examples C + O2  CO2 2H2 + O2  2H2O

  5. Reactants • A substance or molecule that participates in a chemical reaction • Examples C + O2  CO2 Reactants 2H2 + O2  2H2O Reactants

  6. Products • A substance that forms in a chemical reaction • Examples C + O2  CO2 Product Zn + 2HCl  ZnCl2 + H2 Product

  7. Subscripts • A number written below and to the right of a chemical symbol in a formula • Tells how many atoms of that element are present • Examples • CO2 • H20 • C6H12O6

  8. Coefficients • A number that is placed in front of a chemical symbol or formula • Tells how many molecules of that substance are present • Keeps reaction balanced • Example 2H2 + O2  2H2O

  9. Law of Conservation of Mass • Mass is neither created nor destroyed in ordinary chemical and physical changes • Must start and end with the same amount • Example Log + Fire  Ashes + Smoke 30 kg 1 kg 28 kg 3 kg

  10. Decomposition Reaction • A reaction in which a single compound breaks down to form two or more simpler substances • Example H2CO3  H2O + CO2

  11. Replacement Reaction • A reaction in which one element takes the place of another element in a compound • Example Zn + 2HCl  ZnCl2 + H2

  12. Synthesis Reaction • A reaction in which two or more substances combine to form a new compound • Example 2Na + Cl2 2NaCl

  13. Solution • A homogeneous mixture of 2 or more substances evenly dispersed throughout a single phase • Looks like one thing • Usually when 1 substance is dissolved in another, but not always • Examples: Lemonade, Air, Bronze, Gatorade

  14. Solubility • Ability of 1 substance to dissolve in another • To dissolve more quickly: Crush it, Stir it, Heat it • Solute – the substance that is dissolved • Solvent – what substance is being dissolved in • Example: Sugar dissolves in water

  15. Suspensions • A mixture in which particles of a material are more or less evenly dispersed throughout a liquid or gas • When you shake it, it looks like one thing, but if you leave it setting, particles will settle to bottom • Example: Snow Globe

  16. Colloids • Mixture consisting of tiny particles that are intermediate in size between those in solutions and those in suspensions • Particles aren’t so small that they completely dissolve like solutions, but aren’t so big they settle • These particles can scatter light • Example: Milk, Mayo, Deodorant

  17. Homogeneous Mixture • Looks like or appears to be only 1 substance • Example • Gatorade • Lemonade

  18. Heterogeneous Mixture • Looks like or appears to be more than 1 substance

  19. Pure Substance • Sample of matter, either a single element or a single compound, that has a definite chemical & physical properties • Made of only 1 type of particle • Elements or Compounds • Elements – made of atoms • Compounds – made of molecules

  20. Element • A substance that can’t be separated or broken down into simpler substances by chemical means • Pure substance • Can’t be broken down at all • Made of one type of atom • Found listed on Periodic Table

  21. Compound • Substance made up of atoms of 2 or more different elements chemically combined with specific mass ratio • Can only be separated by chemical changes • Made only of molecules • H20: Water • NaCl: Salt • C6H12O6: Sugar • Fe2O3: Rust • Properties of compound are completely different from the properties of elements that formed it

  22. Mixture • Combination of 2 or more substances that are not chemically combined • 2 or more things physically in the same place • Examples: Salad, Cereal, Pizza, Omelette

  23. Change of State • Change of a substance from one physical form to another • Requires adding or removing energy so that particles can speed up or slow down

  24. Endothermic • Energy is absorbed by a substance or substances

  25. Exothermic • Energy is released from a substance or substances

  26. Melting • Change of state when a solid becomes a liquid • Particles must speed up • Add energy/heat • Endothermic

  27. Melting Point • Temperature at which a substance melts • Water: 32°F or 0°C

  28. Freezing • Change of state from a liquid to a solid • Particles must slow down • Remove energy/heat • Exothermic

  29. Freezing Point • Temperature at which a substance freezes • Water: 32°F or 0°C

  30. Evaporation • Change of a substance from a liquid to a gas (only on surface) • Particles (on surface) must speed up • Add energy/heat • Endothermic

  31. Boiling • Change of a liquid to a gas (throughout an entire liquid) • Particles (on bottom of liquid) must speed up • Add energy/heat • Endothermic **Won’t happen unless air pressure equals pressure in bubbles

  32. Boiling Point • Temperature at which a substance boils • Water: 212°F or 100°C • At Sea Level: boiling depends on air pressure

  33. Condensation • Change of state from a gas to a liquid • Particles must slow down • Remove energy/heat • Exothermic

  34. Sublimation • Change of state from a solid to a gas • Example: Dry Ice • Skips liquid stage • Add energy/heat • Endothermic

  35. To Access the BBC Video: • In Internet Explorer, go to www.tinyurl.com/christscience7 • Click on Unit 2 • Under Class Files/Links, click on Behavior of Matter Test Bite (BBC) • When finished, turn in questions to your period’s colored drawer 

  36. Atoms • Smallest unit of an element that maintains the properties of that element • Can not be broken down into anything smaller • Scientists used to think they couldn’t be split, but we now know that was incorrect

  37. States of Matter • The physical forms of matter, which include solid, liquid, and gas

  38. Solid • The state of matter in which the volume and shape of a substance are fixed • Definite shape • Definite volume • Particles are tightly packed • Particles barely move • They vibrate in place

  39. Liquid • The state of matter that has a definite volume but not a definite shape • No definite shape • Definite volume • Particles move fast enough to separate a little • Allowing them to change shape • Particles do not move fast enough to change volume

  40. Liquid (Continued) • Viscosity: a liquid’s resistance to flow • High Viscosity: Slow Flow (Honey) • Low Viscosity: Fast Flow (Water) • Surface Tension: force that attracts the molecules at the surface of a liquid to form the drop

  41. Gas • The state of matter that does not have a definite shape or volume • No definite shape • No definite volume • Particles move so fast that they completely separate from each other • Allowing them to change shape and volume

  42. Gas Laws • If Temperature remains Constant, Hallway • Volume Increases, Pressure Decreases • Volume Decreases, Pressure Increases • Inversely Proportional • If Pressure remains Constant,  Balloon • Temperature Increases, Volume Increases • Temperature Decreases, Volume Decreases • Directly Proportional

  43. Physical Changes • A change of matter from one form to another without a change in chemical properties • Usually reversible, no change to matter composition • End with the same thing you started with • Examples: • Ripping • Crushing • Cutting • Heating • Cooling • Coloring • All changes of state

  44. Chemical Changes • A change that occurs when one or more substances change into entirely new substances with different properties • Never reversible • End with something different than you started with • Examples: • Soured Milk • Burning • Digesting • Cooking/Baking • Rotting/Spoiling • Tarnishing

  45. Signs of a Chemical Change • Change in color • Change in temperature • Fizzing/Foaming • Sound or light being given off • New smell • New taste • Precipitate – when two liquids are mixed together and form a solid

  46. Mass • A measure of the amount of matter in an object • Mass of an object is the same no matter where it is located • Only way to change is to add or take away matter • Unit/Tool: • Grams (g) • Balance

  47. Weight • A measure of the gravitational force exerted on an object • Changes when the force of gravity changes • Differs on Earth & Mars • Unit/Tool: • Newtons (N) • Spring Scale

  48. Matter • Anything that has mass and takes up space • Made up of tiny particles called atoms • Atoms: smallest particle of matter

  49. Physical Properties • Can be observed or measured without changing the matter’s identity • Adjective – descriptive word • Examples • Color • Smell • Size/Shape • Texture/Taste • Temperature • Density • State (Solid, Liquid, Gas)

  50. Chemical Properties • Substance ability to participate in chemical reactions • Hard to observe • In order to see these you must change the substance into a new substance • Examples • Flammability • Reactivity

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