Exam Review

When should you wash your hands?
After all experiments, even if there were no chemicals involved
How do you mix acid and water?
Slowly pour acid into the water
What is Chemistry?
The study of the composition and structure of matter and the changes it undergoes
Explain why Chemistry affects all aspects of life and most natural events
all of living and nonliving things are matter (and chemistry is the study of that matter!)
How did Lavoisier, the father of modern chemistry, transform chemistry?
From a science of observation to a science of measurement
What is a manipulated variable?
the experimenter changes – independent
What is a responding variable?
the variable that is observed – dependent
What is the difference between observations and conclusions and scientific laws?

Observations are made by using the senses

 Conclusions – statements that summarize the results of the experiment

 Scientific Laws – summarize the results of many experiments

What are the two general steps in successful problem solving?
Develop a plan and implement the plan
What is a physical property?
A quality or condition of a substance that can be observed or measured without changing the substance’s composition
Describe the volume and the shape of the three states of matter
Solid – definite shape and volumeLiquid – no definite shape but a definite volumeGas – no definite shape or volume
What are physical changes?
Changes in matter with out changing the composition
List 9 terms describing physical changes
Boil, melt, freeze, condense, break, split, grind, cut, and crush
Name, describe and give and example of the two types of mixtures

Homogenous – uniform in composition – solutions – Salt water, sport drinks

Heterogeneous – not uniform in composition – soil, beef stew

Distinguish between the two types of matter classified as substances (pure). How are each represented?
Elements: simplest form of matter – Symbols Compounds: substance that contains two or more elements chemically combined in a fixed proportion – Formulas
What is a chemical change?
Changes that produce matter with a different composition than the original matter
List 6 terms describing chemical properties (changes).
Burn, rot, rust, decompose, ferment, explode, corrode

What law explains when a physical change or a chemical reaction occurs the mass of the reactants equals the mass of the products?

Law of conservation of matter
Give the four clues that a chemical change (reaction has occurred)

a)      Transfer of energy ( temperature changes)

b) A change in color

c)      Production of a gas

d) Formation of a precipitate

What are the base units for:

mass

length

amount of substance

time

temperature

Kilogram

Meter

Mole

Second

Kelvin

What is the formal for finding Kelvin?
K = C + 273
What are the four major statements of Dalton’s Atomic Theory?

– All elements are composed of atoms

– Atoms of the same element are identical

-Atoms chemically combine to form compounds in small whole # ratios

– Chemical reactions occur when atoms are separated, joined, or arranged

What destinguishes atoms of one element from other elements?
Number of Protons
Describe the relative mass and charge of electrons, protons, and nuetrons

Electrons- charge of -1 and mass 1/1836

Protons- charge of 1+ and mass of 1(almost = to nuetron)

Nuetron- charge of 0 and mass of 1 (almost = to proton)

2 Major conclusions of Rutherford’s gold foil experiment

Mostly empty space

and

Small dense, positively charged core (nucleus)

What is an Isotope?

Atoms of the same element but different number of nuetrons (same # of protons and nuetrons)

What is the atomic mass of an element?

the weighted average mass of the atoms in a naturally occuring sample of an element
What is a Quantum?
the amount of energy required to move an electron from on energy level to another
The Quantum Mechanical Model is:
the modern model of atomic structure
Configurations and Diagrams are:

the arrangement of electrons in the various orbitals around the nucleus

and

boxes showing the arrangement of electrons

List the 3 rules that govern the writing of electron configurrations and orbital diagrams.

1. Aufbau Principle- electrons occupy lowest energy orbitals first

2. Pauli Exclusion Principle- only 2 electrons in an orbital- opposite spins

3. Hund’s Rule- when filling orbitals of equal energy, one electron in each orbital before a second is added

What are alloys?
mixtures composed of 2 or more elements, one is a metal
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