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
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
