I. Classifying Matter A.Pure Substances 1.Every sample has a fixed, uniform composition 2. Every sample has the same properties Ex. Water ice melts at zero degrees Celsius whether it is in the shape of an ice cube or a glacier Bonus:
3.Two types of pure substances a.Elements smallest component is an atom smallest component is an atom have a fixed composition because they contain only one type of atom have a fixed composition because they contain only one type of atom chemical symbols identify the elements chemical symbols identify the elements carbon, C gold, Au copper, Cu iron, Fe Elements
b. Compounds two or more elements joined together in a fixed ratio two or more elements joined together in a fixed ratio chemical formulas identify the compound chemical formulas identify the compound sugar, C 12 H 22 O 11 water, H 2 O Cupric chloride, CuCl 2 Compounds
Questions Can you visually tell the difference between an element and a compound? Why? How can you tell the difference between an element and compound?
B. Mixtures 1.Properties may vary because the composition of a mixture is not fixed What happens if you evaporate salt water? 2.Composed of a combination of pure substances 3.Can be separated by physical means e.g. boiling, sifting, sorting Mixtures Substance 1 (mica) Substance 2 (Feldspar) Substance 3 (quartz)
C. Types of Mixtures 1. Homogeneous- looks the same throughout, a well mixed mixture 2. Heterogeneous- parts look noticeably different Types of Mixtures slate bricks particle arrangement particle arrangement rock layers
3.Solutions, suspensions, and colloids a.Classification is determined by particle size b.Solutions homogeneous homogeneous one substance dissolves into another substance one substance dissolves into another substance composed of very small particles that will not settle and cannot be filtered composed of very small particles that will not settle and cannot be filtered particles cannot be seen and will not scatter light particles cannot be seen and will not scatter light Solutions
c. Colloids homogeneous homogeneous composed of small particles that will not settle and cannot be filtered composed of small particles that will not settle and cannot be filtered particles are not visible and will scatter (block) light particles are not visible and will scatter (block) light Colloids
d. Suspensions heterogeneous heterogeneous particles are large enough to settle if left alone particles are large enough to settle if left alone can be separated by filtration can be separated by filtration particles are visible and will scatter light particles are visible and will scatter light Suspensions
II. Physical Properties of Matter A.Are characteristics of a material that can be observed or measured without changing the composition of the material B.Help identify a substance C. Allow mixtures to be separated
Physical properties-examples D.Examples 1.Viscosity a.Resistance of a liquid to flow b.The higher the viscosity the thicker the liquid 2.Conductivity- Ability to allow heat or electricity to flow through a material Which has more Viscosity?
Physical properties-examples 3.Malleability- the ability of a solid to be hammered without shattering 4. Hardness 5. Melting Point 6.Boiling Point 7.Mass- the amount of matter 8.Volume- the amount of space occupied 9.Weight- force of gravity acting on a mass 10.Density
Physical properties-examples Density a.Mass per unit volume b.The density of water is 1.0 g/mL c.The density of a substance is unique to the substance at a given temperature mass (grams) volume (milliliters or cm 3 ) D =D =D =D =
Things that make you go hmmmm. If the red dots represent matter and the Lt. blue ovals represent space, which of the above would have the most density?
Density Practice Lets Practice! What is the density of an object if it has a mass of 96.5 g and a volume of 5 mL? What is the object made of? mass (grams) volume (milliliters) D =D =D =D = 96.5 grams 5 milliliters D =D =D =D = 19.3 g/mL gold
Density Practice mass (grams) volume (cm 3 ) D =D =D =D = m =m =m =m = If the density of a diamond is 3.5 g/cm3, what would the mass of the diamond be if it takes up 0.5 cm3 of space? 0.5 cm 3 3.5 g/cm 3 1.75 grams
III. Separation of Mixtures Using Physical Properties A.Pick it apart- large particles, heterogeneous B.Use a Magnet- Fe
C. Sifting- separation by size (large) D. Filtration- separation by size (small) Separation Cont’
E. Solubility- dissolving in water F. Distillation- solutions based on boiling points Separation Cont’
G. Decant- pour off the top (density) Separation Cont’ Can you Can you solve this mystery? this mystery?
IV. Chemical Properties of Matter A.The ability to produce a change in the composition of a substance B.Two common examples 1.Flammability 2.Reactivity
V. Chemical and Physical Changes A.Chemical Changes 1.When a substance changes into a new different substance 2.Occurs during chemical reactions 3.Examples: rusting rustingburning
Chemical changes Continued 4.Evidence of a chemical reaction a.Change of color b.Production of a gas (effervescence) c.Formation of a solid from liquids (precipitate)
Physical Changes B.Physical Changes 1.When a substance’s physical appearance is changed 2.The substance remains the same 3.Melting or freezing When wood is chopped it Looks different but remains wood When substances freeze or melt they do not change what they are made of.
Physical Science CSI A statue made of pure platinum ($1250.00 / gm) was stolen from the National Museum. The thief ground the statue up into powder and hid it in his apartment, in hopes of recovering it at a later date. A search of the apartment revealed no signs of the powder. The only object not searched was the thief’s salt water fish tank. It is suspected that the remnants of the statue are somewhere in the fish tank. The tank was delivered to your lab at CSI for examination and a hopeful recovery of the platinum. Explain how you could use Filtration, Distillation, and physical properties to complete this task. Go Back Go Back
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