MODULE 1 Flashcards
Chemistry is the central science because ______________.
it affects a lot of fields.
Steps under Scientific Method
- Think of an idea
- Plan your experiment.
- Research your topic.
- Experiment.
- Collect and record data.
- Come to a conclusion.
These are guesses that can be tested by experimentation.
Scientific Hypotheses
These are useful for predictive value and can be modified or discarded.
Scientific Theories
These are data summarized in brief statements.
Scientific Laws
These use pictures for invisible processes to give way for easier visualization.
Scientific Models
These are examples of scientific models
Newton’s Law of Inertia
Einstein’s Special Theory of Relativity
Deals with the study of Matter, all in terms of composition, structure, properties, transformations, and energy involved in such transformations.
Chemistry
Matter
anything that occupies and has mass; material of the universe
Mass
measures the quantity of matter
Weight
gravitational force of attraction exerted by the Earth on a body
What are the five physical states of matter?
- Solid
- Liquid
- Gas
- Plasma
- Bose-Einstein Condensate
Solid
incompressible and has definite shape and volume
Liquid
indefinite shape but definite volume and is incompressible
Gas
indefinite shape and volume
Plasma
consists of highly-charged particles with extremely high kinetic energy/ion-charged gases (stars, interior of the sun, neon signs from ionised noble gases, etc.)
Bose-EInstein Condensate
has properties of a superfluid (fluid that flows without friction); almost no kinetic energy; evident in Rubidium which are clumps of atoms behaving as a single atom.
What are the two properties of matter?
- Intrinsic
- Extrinsic
Intrinsic Properties
Independent of the amount of material
Extrinsic Properties
Dependent on the amount of material
Physical Properties
measured without changing the basic identity of the substance (e.g. colour, density, odour, melting point)
Chemical Properties
describe how substances react or change to form different substances (e.g. hydrogen burns in oxygen)
Physical Changes
no change in the composition of matter, only physical appearance changes
What are examples of physical changes?
- Changes of state/phase (e.g. melting, evaporation, sublimation, freezing, condensation, deposition)
- Dissolving solute in solvents (e.g. table salt or sugar or sodium chloride in water; INTERACTED, not reacted)
Changes from one physical state to another involves _______________.
Absorption/release of energy
Gas has the highest Kinetic Energy because it _______________.
moves around constantly, meaning it takes in energy (+).
Solid has the lowest Kinetic Energy because ________________.
It is compact, meaning a transition to a solid state indicates a release of energy (-).
Because there is an absorption of energy, a substance is cold to the touch. What is this property called?
Endothermic
Because there is a release in energy, a substance is hot to the touch. What is this property called?
Exothermic
Chemical Changes
change in the composition of matter; both intrinsic and extrinsic properties are changed; represented by a chemical reaction
This can be described by chemical equations
Chemical Reactions
These are examples of chemical reactions
- When pure hydrogen and pure oxygen react completely, they form pure water. In the flask containing water, there is no oxygen or hydrogen left over.
- When iron reacts with oxygen in the presence of warer or air moisture, a new substance is formed, commonly called rust.
What are the two classifications of matter?
- Pure Substances
- Mixtures
Pure Substance
definite composition and properties
simplest type of matter, cannot be decomposed into simpler substances via chemical reactions. It can be found in the Periodic Table and can have a symbol.
Elements
combination of elements in a definite ratio by mass, can be decomposed into the constituent elements.
Compounds
formed by covalent bonding of the component atoms; could be a compound (H2O) or one type of element like diatomic gases (O2)
Molecules
Allotropes
some elements exist in different forms (e.g. carbon - diamond, graphite, graphene, etc.; oxygen - O2, 03; phosphorus - red, white, black, and purple)
Heterogeneous mixtures
made up of two/more phases; indefinite composition and properties
Homogeneous mixtures
one phase only; definite composition and properties
Colloids
intermediate phase (1-100 nm)
Solutions
homogeneous; one phase, usually prepared with definite proportions of solute (the dissolved component) and solvent (the dissolving component in larger amount)
Suspensions
heterogeneous; separate into layers/phases over time; can separate particles via filtration
Colloids
mixtures with particle size (1-1000 nm), intermediate between that of solutions and suspensions, do not separate into layers and cannot be filtered; can scatter light
light scattering by particles in a colloid/very fine suspension; also known as Willis-Tyndall scattering.
Tyndall Effect
