Exam 1: Chapters 1, 2 and 3 Lecture Notes Flashcards
What is chemistry
The study of the composition and structure of materials and of the changes that matter undergoes
What is matter
Anything that occupies space and has mass
What characteristics of matter change during a reaction
Composition, structure, properties
What is green chemistry
Utilizing a set of principles that encourages alternative ways of generating new and existing chemical products without unnecessary risk to human health and population
What is the purpose of the scientific method
Experiments must be done in a controlled way so that results can be reproduced
What is a hypothesis
a statement that tries to explain something in a common way
What saying was Louis Pasteur known for
“chance favors the prepared mind”
What is the purpose of an experiment
an observation of a natural phenomena carried out in a controlled manor so that results can be duplicated and rational conclusions can be made
What is a theory
A tested explanation of a basic natural phenomenon, we cannot prove a theory to be true
What is a law
A concise statement or mathmatical equation about a fundamental relationship or occurrence in nature
What is the Phlogiston Theory, and an example of it
A theory in the 18th century that said when combustible bodies burn they release “phlogiston”
ex) wood=>burn it=>ash+phlogiston
(thought this because ash weighs less then the wood)
Law of Conservation of Mass
The total mass remains constant during a chemical reaction, and mass is neither created nor destroyed
Characteristics of solid matter
- incompressible
- fixed shape
- fixed volume
Characteristics of liquid matter
- incompressible fluid
- no fixed shape
- fixed volume
Characteristics of gas matter
- compressible
- no fixed shape
- no fixed volume
What is a physical change
- A change in the form of matter (not chemical identity)
- reversible
- no new compounds
What is a chemical change
- transformation of one (or more kinds) of matter into a new kind of matter (or several new kinds of matter)
- new compounds are formed
What is a physical property and an example of it
a characteristic that can be observed for a material without changing its chemical identity
ex) state of matter or color
What is a chemical property and an example of it
a characteristic of matter involving chemical change
ex) acidity or reactivity
Can mixtures be seperated
mixtures can be seperated by physical methods into 2 or more substances
elements
A type of matter that is composed of atoms with the same atomic number (# of protons in the nuclei)
compounds
a substance that contains 2 or more elements
What is the Law of Definite Proportions and who is responsible for it
In a pure compound, the elements are always present in a definite proportion or % by mass (no matter what method of preparation) (Proust)
Law of Constant Composition
a given chemical compound alwas contains its component elements in a fixed ratio
heterogenous mixtures and examples
Components vary and can seperate from eachother
ex) milk, ketchup
homogenous mixtures and examples
uniform composition and properties
ex) vodka
Measurment and their requirements
the comparison of a physical quantity, by measuring with a unit of measurement (fixed standard of measurement)
requires a measured number and the unit
accuracy
how close a measurment is to the true value
precision
how close a set of measurments are to each other
What digits are significant
all non-zero digits are significant
When are zeros significant
- zeros betweem sig figs ex) 606
- zeros to the right of the decimal ex) 2.0
- 9.00 (3 sig figs)
When are zeros insignificant
- zeros to the left of the first nonzero digit ex) .08
- zeros at the end of a nondecimal number ex)900 or 9x10^2
multiplication and division sig fig rule
smallest amount of sig figs
error
difference between the true value and what you estimated or measured
random error
scattered around average value
systemstic error
error due to equitment
temperature and how it flows
measure of “hotness”. heat flows (energy) from an area of higher temp to lower temp
temperature units
- celsius, *C
- fahrenheit, *F
- kelvin, K
Fahrenheit to celsius conversion
C= 5/9 (F-32)
Celsius to fahrenheit
F=(C x 9/5) + 32
Celsius to kelvin
K=C+273.15
equation for force
massxacceleration
pressure
force per unit area
equation for energy
forcexdistance
equation for density
d=m/v
what is the density (and necessary temperature) of water
1 g/mL @ *4 C
What were the 4 postulates of Dalton’s Atomic Theory of Matter
- Elements consist of tiny indivisible particles called atoms
- An element is a type of matter of only one kind of atom, and each atom has the same properties and mass
- Compounds are formed when atoms of different elements combine in small whole-number rations (almost like the law of definite proportions)
- Chemical reactions only involve the rearrangement of atoms present in the reacting substance to give new chemical combinations (almost like the law of conservation of mass)
Dalton’s Law of multiple proportions
If 2 elements form more than one compound the ratios of the masses of the second element to a fixed mass of the first element will also be in small whole numbers