notes on matter

Unit 1 Notes
Chapter 3

Matter
Observation v. Inference
• Observation:
• Quantitative or qualitative
• ___________________________________________________
• Inferences:
• Something that you know from ____________________________
• Ex. “made of wood”, “wax”
Physical v. Chemical Properties
• Physical Properties:
• Can be observed without changing the chemical makeup of a substance
• Examples:
• Chemical Properties:
• Describes a chemical change & the kinds of chemical reactions that a substance undergoes
Examples:
Physical Changes
• Changes in physical properties
• ______________________________________________________________________
Examples:

Chemical Changes
• One or more substances (reactants) are transformed into one or more difference substances (products)
• reaction of sodium with water

Evidence of Chemical Reactions
• __________________________________________
______________________________________: gives off heat
• ______________________________________: absorbs heat from surroundings
• __________________________________________
• __________________________________________
• __________________________________________
• __________________________________________
Conservation of Mass
• Late 18th century, scientists started to gather quantitative data during experiments
• Using analytical balance, found that the mass before and after chemical reactions was the same
• Occurred repeatedly so they summarized in scientific law
• ______________________________________________________________________

Matter Mixtures

Elements & Compounds
• Element:
• Pure substance that cannot be separated into simpler substances by physical or chemical means
• Periodic Table: organizes elements based on physical and chemical properties
• Compound:
• combination of 2 or more elements that are combined chemically
• Properties of cmpd differ from those of elements (salt and water)

Mixture
• Combination of 2 or more pure substances in which each substance keeps individual chemical properties
• ________________________________________ mixtures
• Not blended evenly, separate substances remain distinct
• ________________________________________ mixtures
• Constant composition throughout; always has single phase
• Also called __________________________________
Separation Techniques
• Mixtures can be separated by differences in physical properties.
• Centrifugation (using a centrifuge)
• Separates mixtures of undissolved solids from liquids by density.
• As the centrifuge spins the mixture, the larger particles fall to the bottom of the centrifuge tube.
• This is how platelets are separated from the liquid portion of your blood at medical laboratories.
• Distillation:
• Separates mixtures of liquids by boiling point.
• A heating mantle would be held on the ring clamp on the left in order to heat the mixture to the boiling point of the liquid to be recovered.

• Filtration:
• Separates mixtures of undissolved solids from liquids by particle size.
• The filter can be paper as shown above, or a synthetic membrane, as shown on the below.
• The solid particles in a mixure are trapped on the filter, and the liquid portion (the filtrate) is collected in a receiving flask, beaker, or other suitable container.
•
•
• Chromatography:
• Separates mixtures based on attractive forces between the particles of two different phases. (solubility)
• The more the component is attracted to the mobile phase (the liquid moving up the paper) the higher the component travels up the paper.
• The more the component is attracted to the stationary phase (the paper which is not moving) the more it is retained or held back by the paper.