Topic 4: Matter, Phases, and Gas Laws Flashcards
What is matter defined as?
A PURE substance or MIXTURE of substances
What are substances?
-Elements and compounds
-Has a fixed composition and uniform properties throughout the sample
What are mixtures?
-composed of two or more different substances which retain their original properties
-substances may be physically separated
-May be homogeneous (uniform- a solution) or heterogeneous (uneven)
How can substances in a mixture by separated? What are some processes used to do this?
By size, polarity, density, boiling and freezing points, and solubility
-distillation
-filtration
-chromatography
-evaporation
What is an element?
A substance composed of atoms with the same atomic number, they cannot be broken own by chemical change
What is a compound?
Two or more elements bonded together
-substances that form a compound will gain new properties
-ratio of substances is a compound in CONSTANT (water is always 2:1 of hydrogen to oxygen)
Exothermic vs endothermic
Exothermic: heat exits
Endothermic: heat enters
-chemical and physical changes can be either
Properties of liquid
-constant volume
-changing shape
-particles are mobile, held together by strong attraction
Properties of solid
-constant volume and shape
-particles are held in rigid, crystalline structure
Properties of gas
-no set volume or shape
-will completely fill any closed contained
-particles have largely broken free of the forces holding them together
What is a heating/cooling curve?
-traces the changes in temp. of a substance as it changes from S to L to G or G to L to S
-flat line= phase change while no change in temp.
-as temp. increases, kinetic energy increases
Heat of Fusion
the energy needed to convert one gram of a substance from SOLID to LIQUID
Heat of vaporization
the energy needed to convert one gram of a substance from LIQUID to GAS
Specific heat (C)
the energy required to raise one gram of a substance 1 degree (celcius or kelvin)
Combined gas law
States relationship between pressure, temperature and volume in a sample of gas
-Pressure and volume: INVERSE
-Temperature and volume: DIRECT
-Temperature and pressure: DIRECT
Ideal gas
hypothetical gas model where molecules do not repel or attract each other and move in straight lines
A real gas is most like an ideal gas when it’s at LOW temperature and HIGH pressure
What does it mean when equal volumes of gas are at the same temp and pressure?
They will have an equal number of particles
Kinetic Molecular Theory (KMT)
For an ideal gas, says that all gas particles…
-are in random motion
-no forces of attraction between them
-negligible volume
-have collisions that result in the transfer of energy from one particle to another, but no net loss of energy from this collision
Scientific notation
4.2x10^3
