Chem final - Exam 1 ch E/1 Flashcards
Law of conservation of mass
-Matter is neither created or destroyed
Law of conservation of energy
-Energy cannot be created or destroyed
Pure substances
-One type of particle or component
-Cannot be separated
-Chemically bonded
-Fixed ratio
-Lines connecting or same color
Mixture
-2 or more proportions that can vary from one sample to another
-Not chemically bonded
Heterogenous mixture
-Components vary from one region of the mixture to another
-Not even
Homogenous mixture
-Same composition throughout
-Mixed evenly
Element
-Pure substance made of one type of atom
-Periodic table
Compound
-2 or more different elements chemically bonded
-Fixed ratio
Atoms
-Smallest unit
-Periodic table
Molecules
-2 or more atoms chemically bonded
Precision
How consistently you can get the same results
Accuracy
How close you are to the true result
Addition/subtraction sig figs
-Use least amount of decimal places
Multiplication/division sig figs
-Use least amount of sig figs
Density equation
density = m/v
to find mass in the densest equation
mass = d * v
To find volume in the density equation
Volume = m/d
Density of water at 25 c
1g/1mL
Law of multiple proportions
-When elements combine to form different compounds the ratios of their masses can be expressed as whole numbers
Law of definite proportions
-A given compound always contains the same proportions of elements
-2 H and 1 O is always water
Atomic theory
-Each element is composed of tiny indestructible particles called atoms
-All same elements have same mass/same everything
-Atoms combine in whole number ratios
-Atoms of one element can only change the way they’re bound
Isotope
-Same number of protons
-Diff number of neutrons
How to find neutrons
Mass number - atomic number
How to find mass number (top number on square)
-Protons + neutrons
