Unit 2 - Matter and Energy Flashcards
As heat is added to a substance undergoing a phase change, the temperature remains constant because the energy is being used to —
overcome intermolecular forces
Charles Law (gas is held at a constant pressure, then its volume is directly proportional to the absolute temp) this law explains—?
Gas-filled ballon expands when heated
Pressure and Volume are
Inversely proportional
Most efficient way to determine whether a chemical reaction is exothermic is by using
A thermometer (temperature probe)
According to the kinetic-molecular theory of gases, molecules of an ideal gas—
Undergo elastic collisions
strongest intermolecular forces to least
Solid - Liquid - Gas
In reactions:
Exothermic has heat —
Endothermic has heat—
- Releasing
2. Absorbing
Definite shape and volume
Incompressible, does not expand when heated
Molecules tightly packed
Solid
Definite volume (shape of container)
Molecules not rigidly packed
Can move past each other, incompressible
Low expansion on heating
Liquid
No definite shape or volume
Molecules loosely packed
Easily compressed
Gas
Are particles highly attracted to each other in solids or gases
Solids
Gases have less attraction bc of distance
Energy - highest to lowest
Gas - liquid -solid
Makes assumptions regarding the size, motion and energy of particles. Described behavior in terms of particles in motion
The Kinetic Molecular Theory
Gas particles are smaller in size so no repulsive or attractive forces
Particle Size
All particle in gas have same mass, but not same energy. If temp increases, kinetic energy increased and vice versa
Particle Energy
Pressure is what to volume
Inversely proportional
Temperature and volume are
Directly proportional
Pressure and temperature are
Directly proportional
What happens to ice when it is placed in water?
Ice absorbs energy from water which is used for breaking force of attraction between ice particles, then making ice melt
Endo where energy is what in equation
Eco where energy is what in equation
- First
2. Last
How does behavior of molecules change as a substance is heated
Molecules will move faster due to increase in kinetic energy
What if more substance was added to a heated substance?
The motion of molecules would slow down due to cedrease in kinetic energy
In what phase(a) does a substance exist at its triple point
Solid, liquid, gas
What causes cloudy layer outside of glass on hot day?
Different temps inside and outside glass
