Sci 1 Flashcards
What are the three components of a mass spectrometer
ion source, mass analyzer, and detector
What three areas of interest did John Dalton have?
chemistry, meteorology, physics
What Greek philosopher first proposed the concept of atomism?
Leucippus
Who Democritus a student of?
Leucippus
For how long did Dalton maintain daily records of teh weather?
57 years
When did Dalton start keeping daily records of weather?
1787
What interest was sparked by Dalton’s interest in weather?
gas
Where did Dalton first present his papers on gases and their behavior?
Manchester Literary and Philosophical Society
What did Dalton’s law of partial pressures state?
the total pressure of a mixture of gases is equal to the sum of the pressures of each individual gas
Which two French chemists did Dalton draw on?
Antoine Lavoisier and Joseph Louis Proust
Who confirmed that burning hydrogen produced water?
Cavendish
During what two centuries did the Scientific Revolution occur?
sixteenth and seventeenth
With what Greek philosopher is the four elements view associated?
aristotle
What field did chemistry primarily overlap with in the sixteenth and seventeenth centuries?
alchemy
What did scientific study transition towards in the seventeenth century?
empiricism
In what way did chemists first perform calculations of the mass of an atom?
measuring the relative masses of atoms in a compound
What is the mass ratio of HF?
1:19
What instrument do chemists use to measure the mass of an atom?
mass spectrometer
What type of ions are typically used in a mass spectrometer?
positive
What method of detection do airport spectrometers often use?
cycling magnetic field
During what century did Leucippus live?
fifth
Who proposed the law of conservation of mass?
Lavoisier
When was Proust’s law of definite proportions put forth?
1799
What does Proust’s law of definite proportions state?
a substance is always composed of the same proportion of each element
Who proposed the law of multiple proportions?
Dalton
When was A New System of Chemical Philosophy published?
1808
Who wrote A New System of Chemical Philosophy?
Dalton
What two flaws of Dalton’s theories are noted in the guide?
Different isotopes can have different masses and atoms can be broken down further
What is the arrangement of protons and neutrons forming a nucleus called?
nuclide
What is the top number in the symbol for isotopes?
mass number
what is the bottom number in the symbol for isotopes?
proton number
At what mass are carbon atoms radioactive?
14
What is the atomic mass of Hydrogen?
1
What is the atomic mass of helium?
4
What is the ratio of deuterium to hydrogen?
1:6,500
What nuclide is most commonly use in fusion reactors?
deuterium
What isotope is deuterium combined with in fusion reactors?
tritium
What is the half life of C-14?
5,730 years
What is the half life of cobalt 60?
5.3 years
Who created the atomic model with stationary orbits for neutrons?
Bohr
How many electrons can occupy the same exact orbit?
two
What is the atomic model called in which electrons are not at exact distances and do not rotate in orbits?
quantum mechanical model
What is the photoelectric effect?
A photon transfer energy to an electron which is emitted from a metal surface
What device uses the photoelectric effect?
digital cameras
What experiment showed the wave properties of electrons?
Davisson-Germer experiment
What occurred in the Davisson-Germer experiment?
electrons scattered from a nickel crystal
How many groups are on the periodic table?
18
How many “A” groups are in the periodic table?
8
How many “B” groups are in the periodic table?
10
When does a new period begin?
When a new orbital is formed
When does a new period begin?
left to right
Are nitrogen or carbon atoms smaller?
nitrogen
What is the energy required to entirely remove an outer electron from an atom called?
ionization energy
Ionization energy increases from __ to __ on the periodic table
left to right
Does nitrogen or carbon have a higher ionization energy?
nitrogen
Are the elements of periods or groups more similar?
groups
Does ionization energy increase or decrease down a group of the periodic table?
decrease
does electron affinity increase or decrease down a group?
decrease
Who devised a method of evaluating electronegativity?
Pauling
Do pauling electronegativities increase or decrease going down groups in the table?
decrease
What type of bond will two atoms form if the difference in their electronegativies is large?
ionic
What do atoms with electronegativity differences between .5 and 1.8 form?
polar covalent bond
What do dipole moments provide a measure of?
molecule’s polarity
What is a group of atoms held together by a strong covalent bond called?
molecule
What causes the high boiling point of water?
strong intermolecular forces
What is the boiling point of methane?
-162 c
What is the force of attraction between positive and negative charges called?
electrostatic force
What are the three types of bonds?
ionic, covalent, or metallic
What is a metal called when more than one element is present?
alloy
What two elements make up brass?
copper and zinc
What do molecules with partial charges permanently have?
van der Waals forces
When are molecules said to be polar?
a permanent distance can be measured between the positive and negative charge centers
What type of temporary dipole is given in the guide?
induced dipole
who explored induced dipoles?
Fritz London
What are induced dipoles known as?
London dispersion forces
What type of molecules can London dispersion forces occur between?
nonpolar
When are hydrogen bonds formed?
electronegative atom bonds with a hydrogen that is covalently bonded to another strongly electronegative atom
What two scientists first created a model of DNA based on X-ray studies?
James Watson and Francis Crick
Who conducted the X-ray studies of DNA used by Watson and Crick?
Franklin and Wilkins
Who unwittingly produced hydrogen in the sixteenth century?
Paracelsus
What did Robert Boyle discover about hydrogen?
it was much less dense than air
Who identified hydrogen “as an element distinct from other gases?”
Henry Cavendish
What was flammable air also known as in the eighteenth century?
phlogiston
Who named hydrogen?
Antoine Lavoisier
What type of bond creates a three-dimensional structure?
ionic bond
How many covalent bonds can carbon hold?
four
What is an example of a covalent network?
diamond
What is movement over long distances called?
translational motion
Where was Gilber Lewis a chemist?
University of California
What is the number of electrons involved in bonding called?
Valence
What is usually shown in a lewis structure?
valence electrons
What are electron pairs that are not involved in bonding called?
lone pairs
What kind of bond is formed when an atom overlaps one electron orbital?
single covalent
What kind of bond is formed when an atom overlaps two electron orbitals?
double covalent
What is the process in which two electron orbitals combine to form new orbitals called?
hybridization
What process can be used to rationalize the symmetric shapes of many molecules?
hybridization
What kind of molecular orbital is formed when formed when the MO is concentrated along a line connecting the atoms?
sigma bond
What kind of molecular orbital is formed when the electron wave shape is between the atoms but away from the center line?
pi bond
What type of MO is formed when 1s AOs overlap?
sigma
What type of MO is formed when p AOs overlap?
pi
How is oxidation state calculated?
comparing charges before and after bonding or ionization
What does VSEPR stand for?
Valence Shell Electron Pair Repulsion Model
What does the VSEPR Model propose?
negatively charged electron pairs will mutually repel one another in three dimensions
