Chem Flashcards
What Does “WHMIS” stand for?
Workplace Hazardous Materials Information System
What is the purpose of WHMIS?
WHMIS is designed to ensure that people working with
chemicals know how to:
-handle chemicals safely
-dispose of them safely
What does “MSDS” stand for?
Material Safety Data Sheet
All chemicals are shipped with a “MSDS”, what do these sheets include?
-Scientific Names and other common Names
-Physical Properties
-Chemical Hazards
-How to Handle, Store, and Dispose of them Properly
-The procedure to follow in case of an incident
What 2 types of change can a substance go through?
Chemical and Physical
What is Chemical Change?
-When substances react with each other, their atomic/molecular structure changes
-Bonds are broken and reformed to form new substances
-Chemical changes are difficult, if not impossible, to reverse
What is Physical Change?
-A substance changes in form but not in chemical composition
-No new substances are formed
Who are the 4 old dudes?
John Dalton, JJ Thomson, Ernest Rutherford, and Niels Bohr
What is Dalton’s Atomic Theory?
-All matter is made up of small particles called atoms
-Atoms cannot be created, destroyed, or divided into smaller particles.
-Compounds are formed when atoms of different elements combine in fixed, or definite, proportions.
-Chemical reactions change the way atoms are grouped, but the atoms themselves are not changed in reactions.
-All atoms of the same element are identical in mass and size, but they are different in mass and size from the
atoms of other elements.
What is Dalton’s Theory referred to as?
The Billiard Ball Theory
What is the JJ Thomson Atomic Theory? And what did he use the determine this?
JJ Thomson used the Cathode ray to determine that the “ray” was actually a stream of negatively charged objects.
He proposed that atoms were a sphere of positive charge in which negative particles were embedded
What was JJ Thomson Theory called?
It is commonly referred to as either the “Raisin Bun Theory” or the ““Plum Pudding Model”
What was JJ Thomson able to determine with his experiment?
He was able to determine the charge & mass of the electron
What was Ernest Rutherford’s Theory? And what was his experiment?
He directed a stream of alpha paritcles (+ charge) toward thin gold foil.
-he predicted that the particles would collide with the gold atoms and change directions slightly
Was Rutherford’s prediction wrong? If so why?
It was correct, but there was something unexpected. Some of the particles bounced back from the foil.
What did Rutherford conclude from his experiment?
-because most of the particles did bounce on anything he concluded most of the atom was empty space
-whatever the particles bounced back on had to be very small and very positive
What did Rutherford propose for the Atom?
Nucleus
-extremely small, contains nearly all the mass of
the atom.
-contains protons (+ charge), and neutrons
(neutral charge).
Electrons (- charge)
-very little mass, move around the nucleus like
planets orbiting the sun.
What was Rutherford’s Theory called?
Solar-System Model
What did Niels Bohr propose for his theory?
That electrons are found in energy levels,
and cannot be found in between these energy levels.
What is the “Bohr Model”?
Electrons orbit the nucleus of an atom in set energy levels.
What was the Bohr Model called?
Planetary Model
What did James Chadwick discover and conclude?
-After bombarding beryllium atoms with alpha particles, Chadwick discovered
an unknown form of radiation
-He concluded that the presences of another subatomic particle that was
neutral and similar in mass to that of the positive charge in the nucleus
What are the respective charges of the Proton, Neutron, and the Electron?
Proton = 1+
Neutron = 0
Electron = 1-
In an element how do you determine the number of protons? Number of electrons? And the number of Neutrons?
protons = atomic #
electrons = atomic #
neutrons = mass - atomic #
