9/28/22 - Chemical Properties and Energy Flashcards
1st Law of Thermodynamics
Energy is not created or destroyed, but can be converted.
Central idea in chemistry?
Study observable changes to understand unobservable, particle-level causes.
Chemical change
AKA Chemical reaction, when substance(s) are converted to substance(s) with different composition and properties.
Chemical property
A quality a substance shows as it changes into or interacts with another substance.
Chemical property examples
Flammability, corrosiveness, reactivity with acids
Evaporation - chem or phys change?
Physical
Extensive properties
Properties that depend on the amount of a substance
Extensive property examples
Heat, volume, mass
How does chemical potential energy arise?
Positions and interactions of a substance’s particles.
When a high energy substance is converted to low energy, some chemical potential energy is converted to kinetic energy.
If a physical change is caused by heating, can it generally be reversed by cooling?
Yes
Intensive properties
Properties that don’t depend on the amount of a substance
Intensive property examples
Color, temperature, density
Physical change
When a substance changes physical properties but not its composition.
Physical property
A quality a substance shows by itself without changing into or interacting with another substance.
Physical property examples
Color, melting point, density, mass
