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
Potential energy
Energy due to an object’s position relative to other objects.
What is a theory?
A comprehensive explanation, supported through experimentation, and predictive of future results.
Which energy situations are favored?
Stable and low energy.
Weight falls when released, making a situation lower energy and more stable.
