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TOPIC : Heat AIM : How do substances change from one phase to another?. States (phases) of matter. 1. SOLID Molecules packed closely together Vibrate in place. Definite volume & shape. 2. LIQUID Molecules farther apart & move around. Definite volume No definite shape. 3. GAS
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TOPIC: HeatAIM: How do substances change from one phase to another?
States (phases) of matter 1. SOLID Molecules packed closely together Vibrate in place
2. LIQUID • Molecules farther apart & move around
Definite volume • No definite shape
3. GAS • Molecules very far apart & move around very fast • A lot of empty space (smaller density)
4. PLASMA • High energy molecules • Sun, stars, lightening, fluorescent & neon lights
Can you find the different phases of matter in this picture?
2 types of changes 1. Physical change Phase change Does not produce a new substance (change in appearance)
2.Chemical Change Produces a NEW substance Examples: burning, rusting
Raw egg cooked egg Cake batter Cake
Sodium + Chlorine NaCl = Sodium Chloride (salt)
Phase change Physical change Requires heat energy
Freezing Liquid Solid Heat removed
Melting Solid Liquid Heat added
Evaporation Liquid Gas Heat added Vaporization
Condensation Gas Liquid Heat removed
Sublimation Solid Gas Heat added Example: Dry ice (solid CO2 gas)
Solid Gas
Example: Iodine crystals gas (slightly above room temp) Gas Crystals
PHASE CHANGES Add heat Energy absorbed by molecules Melting SL Evaporation LG GAS SOLID LIQUID Freezing LS Condensation GL Remove heat Energy released by molecules
Freezing point Temp at which a liquid freezes (LS) FP of water = 0°C
Melting point Temp at which a substance melts (SL) MP of water = 0°C
Boiling point Temp at which a substance evaporates (LG) BP of water = 100°C
Evaporation occurs at the surface of a liquid (left). When a liquid boils, gas bubbles form throughout the liquid and then rise out of the liquid (right).
Temp of a substance during phase change Stays the same until all of the substance has changed Why? Bc the energy is needed to change the substance, not the temperature
When water reaches its boiling point, it stays at 100°C until it all changes to steam. Them temperature of the steam can then rise above 100°C.
PHASE CHANGE GRAPH FOR WATER GAS Condensation Boiling pt = 100°C 100°C Evaporation T E M P LIQUID Freezing 0°C Freezing/melting point = 0°C Melting SOLID = phase changes Time
What is a mixture? 2 or more substances put together No new substances (not chemically combined) Ex: salt water, salad…
Can be separated • (Boiling, magnets, Filtering…)
What is a solution? Type of mixture 1 substance dissolved in another