Flashcard: Understanding Matter: Physical and Chemical Changes — 20 carte

Physical change — definition?

Change without forming new substances.

Chemical change — definition?

Change forming new substances with different properties.

Reversible change — example?

Melting ice or dissolving salt.

Irreversible change — example?

Burning paper or baking cake.

Signs of chemical change?

Colour change, gas, precipitate, energy change.

Chemical equation components?

Reactants, products, symbols, formulas.

Energy in exothermic reactions?

Releases heat, light, or sound.

Energy in endothermic reactions?

Absorbs heat from surroundings.

Particle vibration in solids?

Particles vibrate in fixed positions.

Particle movement in gases?

Particles move rapidly in all directions.

Particle arrangement in liquids?

Close but slide past each other.

Particle bonds in solids?

Strong bonds, tightly packed.

Reversible physical change?

Melting, dissolving, stretching.

Irreversible chemical change?

Burning, cooking, rusting.

Change of state — process?

Energy transfer causes phase transitions.

Dissolving — role?

Disperses solute in solvent physically.

Particle behavior during expansion?

Particles gain energy, move apart.

Particle behavior during contraction?

Particles lose energy, move closer.

Signs of chemical reaction?

Gas, precipitate, colour, energy change.

Particle model — explanation?

Matter made of particles in motion.