Exam 1 Flashcards
What is a homogeneous mixture?
Homogeneous mixtures have uniform composition throughout
What is a heterogeneous micture?
heterogeneous mixtures do not have uniform composition throughout
What is John Dalton’s atomic theory?
-All matter is composed of small particles called atoms
-Atoms of a given element are identical in mass and properties
-Atoms of different elements have different masses and properties
-Atoms combine in simple whole-number ratios to form compounds
-Chemical reactions involve the rearrangement of atoms, not their creation or destruction
What are the 3 subatomic particles?
-Protons
-Neutrons
-Electrons
What is the mass of an element determined by?
The sum of protons and neutrons
What are covalent bonds?
Covalent bonds involve the sharing of electrons between atoms
What are hydrogen bonds?
Hydrogen bonds are intermolecular forces that occur between 2 water molecules
Why is water cohesive?
Due to hydrogen bonding
Is water polar?
Yes. It forms strong intermolecular bonds with itself
Is water a universal solvent?
Yes
Equation to get Celsius from Farenheit
C = (F-3)(5/9)
T/F: Exact numbers limit the number of significant figures in a calculated result
False
What scales are used to measure temperature?
Farenheit, Celsius, Kelvin
What is temperature a measure of?
The kinetic energy of molecules
Does heat transfer from cold to hot, or hot to cold?
Heat always transfers from a hotter object to a colder one
Equation to get Farenheit from Celsius
F = (9/5)(C) + 32
Equation to get temperature in Kelvin from Celsius
K = C+273
What is the Law of Constant Composition (Definite Proportions)?
All samples of a pure compound contain the same elements in the same proportion by mass
T/F: The composition of compounds always consistent, regardless of how or where they are formed
True
What do significant figures always include?
-Nonzero digits
-Captive zeros
-Trailing zeros (when right to decimal point, when in scientific notation)
What do significant figures not always include?
-Leading zeros
-Trailing zeros (when left to a decimal point)
When multiplying/dividing, is the answer rounded to the smallest number of decimal places, or the smallest number of sig figs?
The smallest number of sig figs
When adding/subtracting, is the answer rounded to the smallest number of decimal places, or the smallest number of sig figs?
The smallest number of decimal places
What is the density formula?
d = (m/v)
What can density be used for?
Density can be used to determine whether an object will float or sink in a liquid
What did J.J. Thompson experiment with?
Cathode ray tubes
What did J.J. Thompson’s experiments lead to?
The discovery that atoms contain small, negatively charged particles called electrons. No matter what the metal was, the cathode ray tubes would get the same results (deflected towards the positive plate)
T/F: Electrons are heavier than atoms
False. Electrons are way lighter than atoms.
What did Millikan experiment with?
oil drops