Chem 121 - Unit 1 Flashcards
What are the 7 diatomic elements?
Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, and Fluorine
What is a molecular formula?
Gives the true or actual number of the atoms in a molecule
What is an empirical formula?
Gives the simplest whole number ratio of the atoms (most common for ionic)
What is a structural formula?
Gives the number of atoms and the bonds between them
What are intensive properties?
Properties that are independent of the amount of the substance that is present
Ex: Density, boiling point, etc.
What are extensive properties?
Properties that depend upon the amount of the substance present.
Ex: Mass, volume, energy, etc.
What are physical properties?
Properties that can be observed without changing a substance into another substance
Ex: Hardness, color, electrical conductivity, etc.
What are chemical properties?
Properties that can only be observed when a substance is changed into another substance.
Ex: Flammability, corrosiveness, etc.
What are physical changes?
These are changes in matter that do not change the composition of a substance.
Ex: changes of state, temperature, volume, etc
What are chemical changes?
Chemical changes result in new substances.
Ex: combustion, oxidation, decomposition, etc.
What is the first law of thermodynamics?
Energy is neither created nor destroyed.
What is the scientific method?
The process used by scientists to explain observations in nature
What is a natural law?
A natural law is a simple statement describing basic facts or relationships of nature
What is a hypothesis?
A hypothesis is a speculative guess which leads to experiment
What is a theory?
a theory is an explanation of the general principles of certain phenomena with considerable evidence of facts to support it
What are the SI prefixes in order from largest to smallest?
Kilo Hecto Deka Main unit Deci Centi Milli Micro Nano Pico
What is temperature?
A measure of the average kinetic energy of the particles in a sample
What is the Kelvin to Celsius conversion?
K = C + 273.15
What is heat?
A measure of the quantity of energy due to molecular motion (or energy that flows between objects that are at different temps
What is the difference between accuracy and precision?
Accuracy refers to the proximity of a measurement to the “true value” of a quantity, and precision refers to the proximity of several measurements to each other
What is the first law of chemical change?
Law of Conservation of Mass: The total mass
of substances does not change during a chemical reaction
What is the law of conservation of mass?
Mass remains constant during a chemical reaction
What is the second law of chemical change?
Law of Definite (or Constant) Composition: The elemental composition of a pure compound is always the same
What is the Law of Definite (or Constant) Composition?
The elemental composition of a pure compound is always the same
Who discovered the law of conservation of mass?
Antoine Lavoisier
What is the law of multiple proportions?
If elements A and B react to form more than one compound, the different masses of element B that combine with a fixed mass of element A can be expressed as a ratio of small whole numbers (integers).
Who first stated the law of multiple proportions?
John Dalton
Who proposed the atomic theory?
John Dalton
Describe J.J. Thompson’s contribution.
Measured cathode rays, plum pudding model
What is a cathode?
A negative electrode (actually discovered to be electrons)
What did Robert Millikan do?
Determined charge of electrons through Millikan-Oil Drop Experiment
Who discovered radioactivity?
Henri Becquerel, Marie Curie named it
What is radioactivity?
The spontaneous emission of radiation by an atom
Who discovered the nucleus?
Ernest Rutherford
What part of the atom carries the most mass?
Nucleus
Who discovered atomic mass?
Henry Moseley
Who discovered protons?
Ernest Rutherford
What is the atomic number?
The atomic number is equal to the number of protons in the nucleus or to the number of electrons in a neutral atom
What is the mass number?
the total number of protons and neutrons in the nucleus
What is a nuclide?
a particular combination of protons and neutrons
What is an isotope?
nuclides with same number of protons
Who is Dmitiri Mendeleev?
Father of the Periodic Table
How are elements arranged in the periodic table?
By increasing atomic number left to right
What makes up ionic bonds?
A metal and nonmetal
What makes up covalent bonds?
Two nonmetals
What types of bonds are covalent bonds?
Shared electrons
What types of bonds are ionic bonds?
Electron transfer process
What are cations?
Cations are positive and are formed by elements on the left side of the periodic chart
What are anions?
Anions are negative and are formed by elements on the right side of the periodic chart.
What are the greek numerical prefixes (1-5)?
Mono Di Tri Tetra Penta
What are the greek numerical prefixes (6-10)?
Hexa Hepta Octa Nona Deca
