Ch 1 Notes Flashcards
Chemistry is?
The study of properties of matter and the changes matter undergoes
What do chemists do?
They study components of matter and their relative amounts, how components can be separated, and how mixing a substance with another changes the properties of that substance
Matter is?
Anything that occupies space and has mass
Heterogeneous
Nonuniform
Uneven texture, different components that can be seen under a microscope
Homogeneous
Uniform - Solutions
Two or more substances in the same state, same properties in all regions
Pure Substance
Fixed composition
Distinct properties
Free of impurities, cannot be separated by any physical technique
Solutions
Homogeneous mixture
Compounds
Elements united in fixed ratios by a chemical bond
Elemental properties change
% Composition by mass is always the same
Elements
Cannot be subdivided by chemical or physical processes
Substances composed of only one type of atom
Kinetic-Molecular Theory
All matter exists of extremely tiny particles which are in constant motion
Higher temp means faster movement
Solids
Particles packed closely together in a regular array
Vibration happens but particles do not move past each other - rigid substance
Liquids
Particles arranged randomly, fluid, particles are not confined to a specific spot, can move past each other
Gases
Particles under normal conditions are far apart, particles move rapidly because they’re not constrained. Random motion allows particles to fill the container.
Macroscopic
Observations and experiments; changes we can see
Particulate (submicroscopic)
Atoms and molecules are modeled using symbols
Separation
Used to purify physical or chemical properties
Filtration
Uses differences in solubility
Evaporation
Uses solute and solvent differences
Distillation
Uses differences in boiling point
Chromatography
Uses differences in ability to adhere to surfaces
Fractional Crystallization
Uses differences in solubility at different temperatures
Atoms
Smallest particle of an element that retains the chemical properties of that element
Molecules
Smallest discrete units that retain the composition and chemical characteristics of a compound
Physical Properties
color - state - melting point - density - boiling point - solubility - conductivity - malleability - ductility - viscosity
Can be measured without changing the identity of the substance
Temperature Dependence
The numerical values for some physical properties will change with temperature
Extensive Properties
Dependent on the amount of substance
Intensive Properties
Independent of the amount of substance
Physical Changes
Changes in appearance or state while preserving identity of a substance
Chemical Changes
Changes where the identity of a substance is altered through a chemical reaction where reactants are transformed into products described by a chemical equation
Precision
How well multiple determinations agree with each other
Accuracy
Agreement of a measurement with an accepted value for that element
Standard Deviation
A measure of precision
True or False
The mass and number of atoms in a chemical reaction is conserved?
True
True or False
The molecules and number of moles in a chemical equation is constant
False
Temperature Dependence
The numerical values for some physical properties will change with temperature
Extensive Properties
Dependent on the amount of substance
Intensive Properties
Independent of the amount of substance
Physical Changes
Changes in appearance or state while preserving identity of a substance
Chemical Changes
Changes where the identity of a substance is altered through a chemical reaction where reactants are transformed into products described by a chemical equation
Precision
How well multiple determinations agree with each other
Accuracy
Agreement of a measurement with an accepted value for that element
Standard Deviation
A measure of precision
True or False
The mass and number of atoms in a chemical reaction is conserved?
True
True or False
The molecules and number of moles in a chemical equation is constant
False
