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