What is matter?

1. What is matter? • Matter is anything that takes up space and has mass. • Write some examples of matter in this room… • Matter can have many different properties (characteristics that can be used to identify and classify it)

5. solids • A solid has a definite _____________ and _____________ • (“Definite” means you can tell what it is & it is the same) • A solid keeps its shape and volume no matter what it’s in • The particles are closely packed together • The particles do move some: they vibrate in place, but do not move other than that • Let’s demonstrate a solid! shape volume

7. liquids • A liquid has a definite _____________ but not a definite ____________ • The shape of a liquid changes with its container • Particles in a liquid still touch but move freely past each other • Liquids are fluids (a fluid is something that flows) volume shape

9. Properties of liquids • Water molecules are strongly attracted to each other • Surface tension: an inward force that pulls liquid molecules together, forming puddles or drops • Surface tension makes the surface of water act kind of like a skin, so things can float on (and even walk on) water • Viscosity is a liquid’s resistance to flowing (how slowly it flows) • Viscosity depends on the size and shape of the liquid’s particles • Different liquids have different viscosities • Examples: water flows differently than honey because they have different viscosities

13. Non-newtonian Fluids • ketchup • Ants • Mytbusters walk on water • Oobleck on a speaker in slomo

14. gases • Gases have NEITHER a definite ____________ NOR a definite _____________ • In a closed container, gas particles expand to fill it • Gases are also fluids because they flow shape volume

15. Properties of gases • Volume: amount of SPACE matter takes up • The Volume of a gas is the same as the volume of its container • Most of the volume of a gas is empty space • Gases can be compressed (squished) to fill smaller volumes (compressed air is used to fill balloons) • When a gas is compressed, the particles do not change size, they just move farther away from each other

16. Properties of gases • Temperature: a measure of the average SPEED of random motion of particles • The Faster particles are moving, the more ENERGY/HEAT they have and the higher their TEMPERATURE • The particles of gases move the fastest of all the states

18. melting • Changing state from solid  liquid • Pure, crystalline solids melt at specific temperatures called melting points • This is a physical property • The melting point of water is 0 degrees Celsius (32 deg. F) • It stays at 0 degrees until it is done freezing • As a solid melts, its particles begin to move more, and they break away from their fixed positions and can move more freely

22. freezing • Liquid  solid • Reverse of melting • At the freezing point, particles move so slowly they start to get stuck in a fixed position • Particles lose energy • Some things become solid (freeze) at relatively high temps • Ex: chocolate, candle wax, butter

23. vaporization • Changing state from liquid to gasis called vaporization • This happens when the particles in the liquid gain enough energy to move independently (become a gas) • 2 types of vaporization: evaporation & boiling

24. evaporation • Evaporation is vaporization that takes place on the surface of a liquid • Can take place at any temperature • Ex: shrinking puddle

26. boiling • Boiling is vaporization that takes place all over the liquid • Forms bubbles below the surface that rise and escape • Temperature at which a liquid boils is its boiling point • Happens faster than evaporation

29. condensation • Changing state from a gas  liquid • Opposite of vaporization • Occurs when particles of a gas lose enough energy to become liquid • Ex: breathing on a mirror, glasses fogging up, clouds forming (water vapor condensing into liquid droplets—true water vapor is invisible)

31. sublimation • When particles in a solid gain enough energy to turn into a gas (skip the liquid phase) • Happens on the surface (like evaporation does) • Ex: dry ice (solid CO2), snow disappearing without forming puddles first, old ice cubes getting smaller • Opposite of sublimation is gas solid and is called deposition

36. Properties of matter • Used to identify and classify matter. • What are some examples of properties of matter? • Temperature, color, texture, phase (solid/liquid/gas), flammability, etc. • Chemistry is the study of matter and how it changes. • A substance is made of pure matter. It is a single kind of matter and always has the same composition (makeup). • Example: table salt, pure water

37. Physical Properties of matter • Matter has physical properties and chemical properties. • A physical property is a characteristic that can be observed without changing the substance into another substance. • Examples? • Luster (shininess), hardness, texture, color, temperature, conductivity (of heat or electricity), solubility, flexibility(malleability or ductility), freezing point, boiling point, melting point, size (area/length/mass/volume/etc.), brittleness, concentration, density, electrical charge, location, luminance, momentum, opacity, specific heat, velocity, etc..

39. Chemical properties • A chemical property describes the ability of a substance to change into something else. • Examples? • Reactivity, flammability, toxicity, half life • Why is freezing point a physical property and not a chemical property?? • Because when something changes state it is still the same substance

41. Changes in Matter

42. Physical Changes • A physical change changes the form (shape) or appearance of matter but NOT what it is made of • It is still the same substance • Physical changes change physical properties and do NOT change chemical properties • Examples of physical changes? • Crushing, dissolving, bending, tearing • Any changes of state/phase (boiling, melting, evaporating, etc.)

44. Chemical Changes • A chemical change is a chemical reaction in which one or more substances (REACTANT(S)) transforminto something new (PRODUCT(s)) • Atoms are rearranged • The product(s) has different chemical properties from the reactant(s) • You can only reverse a chemical change by doing another chemical change

46. Chemical Changes • Examples of chemical changes? • Photosynthesis, combustion, decomposition, fermentation, rusting/oxidation, cooking, tarnishing, and any other chemical reaction

48. Physical or Chemical Change?

50. Law of Conservation of Mass • In a chemical change, the mass of the products ALWAYS equals the mass of the reactants • This is called the Law of Conservation of Mass • Matter is NEVER created or destroyed—atoms are only rearranged