Chemical reactions · Topic 11 of 15

Energy in Chemistry: Heat & Energy Changes

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Chemistry · energy

Kinetic is motion, potential is stored; temperature is average particle motion; heat flows hot to cold; the sun is Earth's main source.

01 · Two kindsKinetic = motion · potential = stored

02 · Heat vs temperatureTemperature ≠ heat

03 · The sourceSun = Earth's main energy source

Energy = the capacity to do work or to supply heat must know

The sun is Earth's main outside energy source (over 90% of our energy) must know

Thermal energy = particle motion; adding it raises temperature

Chemical energy (food, fuel, batteries) is stored potential energy

Field energy: stored by position in a gravity, electric or magnetic field

Sun (fusion) → light → photosynthesis → chemical energy in food

Energy units: joule (SI) or calorie — 1 cal = 4.184 J

Heat flows hot → cold until the temperatures are equal

Energy is conserved: it changes form but is never created or destroyed

Kinetic = energy of motion; potential = stored energy must know

Temperature = average particle motion; heat = energy in transfer must know

Commonly confused

	Heat	Temperature
What it is	Thermal energy moving between objects	Average kinetic energy of the particles
Big pot vs small cup, same temperature	Big pot holds more thermal energy	Same reading for both
Direction	Flows from hotter to cooler	The difference sets which way heat flows

Same temperature, bigger sample = more thermal energy

Show 2 more facts

Light carries energy in its electric and magnetic fields

Specific heat: energy to warm 1 g by 1 °C — water's is high

Pearl

Temperature tells how fast particles move on average; heat is the energy that moves because two temperatures differ.

Practice this topic, then test the whole section.

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