What are the types of matter?
Not states
Pure Substances and Mixtures
Pure Substances have..
a fixed and definite composition
Mixtures
Contain two or more different substances that are physically combined
Can be physically separated
What are the types of pure substances?
Elements → 1 type of atom (periodic table)
Compounds → 2 or more chemically combined atoms that are always in the same ratio (Water = H₂0)
What are the types of mixtures?
Homogeneous → Uniform composition/ appears the same like milk (although it’s made up of many things)
Heterogeneous → Mixed composition/ appears different like spoiled milk (things are visibly all over)
What are the states of matter (excluding plasma)?
Solid, liquid, and gas
Solids
Shape
Volume
Particle arrangement
Particle interaction
Particle movement
Shape: Definite
Volume: Definite
Particle arrangement: Close; Fixed
Particle interaction: Very strong
Particle movement: Vibrate; Very slow
Liquids
Shape
Volume
Particle arrangement
Particle interaction
Particle movement
Shape: Indefinite (takes the shape of its container)
Volume: Definite
Particle arrangement: Close; Mobile
Particle interaction: Strong
Particle movement: Moderate
Gasses
Shape
Volume
Particle arrangement
Particle interaction
Particle movement
Shape: Indefinite (takes the shape of its container)
Volume: Indefinite (takes the volume of its container)
Particle arrangement: Random; Far apart
Particle interaction: Essentially none
Particle movement: Very fast
What increases the motion of particles?
Heat
Physical Properties
Characteristics observed or measured without changing the composition of a substance
Shape, physical state, boiling/freezing point, density, color
Physical Change
Occurs in a substance if there is
State change
Change in physical shape
No change in identity and composition of the substance
Chemical Properties
Describe the ability of a substance to become one or multiple different substances
Chemical Change
A new substance forms that has new chemical and physical properties
Temperature
Measure of how fast particles move
How hot or cold an object is compared to another object
What type of energy is particle motion?
Kinetic energy
What are the temperature scales?
What kind of unit?
Fahrenheit → U.S Unit
Celsius → Metric Unit
Kelvin → SI Unit
Freezing point of water (all three scales)
Fahrenheit: 32°
Celsius: 0°
Kelvin: 273 K
Boiling point of water (all three scales)
Fahrenheit: 212°
Celsius: 100°
Kelvin: 373 K
Fahrenheit → Celsius Formula
F = 1.8(C) + 32
Celsius → Kelvin Formula
K = C + 273
What is unique about Kelvin?
It is the absolute temperature scale
No degree sign
No negatives
Starts at 0K which the absolute lowest temperature can possibly be
Energy
The ability to do work
Makes objects move
What are the two main types of energy?
Kinetic and Potential
Kinetic Energy
Energy of motion
Swimming, water running down a dam, working out
Potential Energy
Stored energy for use at a later time
Gasoline, coal, food, chemical bonds, compressed spring, water at the top of a closed dam
How is potential energy determined?
By the position of the object and/or the chemical composition of a substance
The ______ particles move the ______ the _______ energy(temperature) of the substance
The faster particles move the greater the thermal energy(temperature) of the substance
Heat
Energy transferred from hot to cold particles
What happens when ice is heated?
The molecules increase motion and eventually have enough energy to change states
Solid → Liquid
Unit of Energy
SI Unit: Joule(J) or Kilojoules (kJ)
Metric Unit: Calories (cal) or Kilocalories (kcal)
The amount of energy needed to raise the temp of water by 1°C
Joule → Calorie Conversion
4.184J = 1 cal
Exact; doesn’t not count toward sig figs
Nutrition
Nourishment or energy obtained from food
Calorimeter
Nutritionists burn food in it
Measures heat transfer
The heat released from burning a food sample is used to determine the energy value for that food
Cal (food label) → cal Conversion
1 Cal = 1000 cal
OR basically, 1 Cal = 1 kcal
Specific Heat
The amount of heat that raises the temperature of 1g of a substance by exactly 1°C
Different for each substance
The ability of a substance to retain heat
What are the units for specific heat?
SI and Metric
SI Unit: J/g°C
Metric Unit: cal/g°C
Specific Heat Formula
heat/(grams x ∆T) = cal(or J)/g°C
Specific heat of water
1.00 cal/g°C OR 4.184 J/g°C
When ocean water cools, the surrounding air
a. cools
b. warms
c. stays the same
b - the water’s heat is released, warming the air
Sand in the desert is hot in the day and cool at night.
Sand must have a
a. low specific heat
b. high specific heat
a - the sand does not retain heat very well
Heat Formula
mass x ∆T x specific heat = cal/J
(specific heat must also match the energy unit)
What are the types of state changes and do they absorb or release heat?
S → L = Melting; absorbs heat
L → S = Freezing; releases heat
L → G = Evaporation/Vaporization; absorbs heat
G → L = Condensation; releases heat
S → G = Sublimation; absorbs heat
G → S = Deposition; releases heat
Exothermic
Releases heat
Endothermic
Takes in heat
What type of state change occurs with dry ice?
Sublimation
Heat of Fusion
Amount of heat released when 1g of a liquid freezes at its freezing point
AND
Amount of heat needed to melt 1g of a solid at its melting point
Heat released during freezing = Heat needed to melt (for any given substance)
w/o changing temperature
Evaporation (water)
Surface molecules gain sufficient energy to become gas
Condensation
Gas looses energy; becomes liquid
Boiling (water)
All molecules gain enough energy to form a gas (vaporize)
Bubbles of water vapor appear throughout the liquid
Heat of Vaporization
Amount of heat to change 1g of liquid to gas at its boiling point
AND
Amount of heat released when 1g of gas changed to liquid at its boiling point
w/o changing temperature
Sublimation
Surface particles of solid become has directly gas
No temperature change
Dry ice goes through sublimation at 78°C
Deposition
Gas particles to solids
Doesn’t pass through the liquid stage
True or False: As a solid melts, its temperature does not change
True; the absorbed heat is used to break the forces of attraction between particles, not to heat the substance
What is the caloric value per gram of carbohydrates, proteins, alcohol, and fats?
Carbohydrates: 4 calories per gram
Proteins: 4 calories per gram
Alcohol: 7 calories per gram
Fats: 9 calories per gram