PHYSICAL CHEMICAL CHANGES Objective To know the difference

PHYSICAL & CHEMICAL CHANGES Objective To know the difference between a chemical and physical change. What names are given to the 4 changes of 1. Melting state? 1. Solid to liquid 2. Liquid to solid 3. Liquid to gas 4. Gas to liquid 2. Freezing 3. Evaporating 4. Condensing

CHANGES OF STATE - PHYSICAL CHANGES Each change of state is given a different name. Gas Boiling Condensing Melting Solid Liquid Freezing

REVERSIBLE OR IRREVERSIBLE? Can you get back what you started with? (Reversible) Or is it changed forever? (Irreversible) I think. . . because. . . I disagree because. . . I agree because. . . Also. . . EXTENSIONHow do you know if a chemical reaction has happened?

SIGNS OF A CHEMICAL CHANGE or s e l Bubb g fizzin ce i n ( ls l e m S nasty!) or gets r… e m r wa flam es o spa r rks Nois es (f r gs t om loud o fizzi quiet ng) ban … co or lde r

CHEMICAL CHANGES Chemical changes (reactions) are usually irreversible. What do you think this means? Example: Frying an egg

OBSERVING – CHEMICAL AND PHYSICAL CHANGES Write down observations and whether you think these are physical/chemical changes and reversible or not: 1. Half a test tube Hydrochloric acid + magnesium strip 2. 1 cm Sodium hydroxide + 1 cm copper sulfate 3. 1 cm Hydrochloric acid + 1 cm sodium hydroxide + Universal indicator 4. Salt + water 5. Melting ice cube

Experiment Ice cube melting Kettle boiling Bunsen burner on Burning toast Dissolving salt in water Boiled egg Magnesium dropped in acid Burning splint Dissolving tablets in water Baked Cake Reversible or irreversible? Physical or chemical change?

PHYSICAL OR CHEMICAL CHANGE? Use mini whiteboards