Quiz 2 and 3 Math/chem review Flashcards
Accuracy is:
The agreement between experimental data and the “true” value
Precision is:
The agreement between replicate measurements.
T/F: One can be precise without being accurate.
True
Density = _____/______
mass/volume
Specific Gravity=
ratio between an object’s density and the density of water.
A value >1 is more dense than water, value <1 is less dense than water.
Chemistry is defined as
the study of matter and it’s changes
Matter is
anything that has mass and occupies space
What is considered the building blocks of matter?
Atoms
Name the 3 parts of an atom
Protons, neutrons and electrons
Do Protons have a + or - charge?
Protons mass =?
Positive + charge
Mass = 1 atomic mass unit (amu)=1.66 x 10 to the -27
The atomic number (Z) identifies the atom by the number of what?
Protons
What is the charge of a Neutron?
Neutral, no charge.
Electrons have what charge? and have a mass of?
Negative
negligible amount of mass.
Cations= + or -
+ charged ions
Anions = + or -
- charged ions
compounds contain
more than one kind of atom in a fixed ration by mass.
ex. CO2 or NaCl
Molecules are:
groups of atoms chemically bonded together into a discrete unit by covalent bonds. The have a neutral charge.
Ionic compounds:
Contain both + and - charged ions with no identifiable units. Attracted by charge and are NOT molecules.
Can a substance be both a molecule and an element?
Yes: O2; neutral charge.
ice melting or boiling water is an example of what kind of change?
Physical change. Same substance, different state.
combustion is an example of what kind of change?
Chemical change. started out as one substance, became another.
_____ properties can be observed and measured w/o changing the chemical makeup
physical
intensive properties include_____
color, shape (does not effect amount or volume)
extensive properties include___
Amount, size, volume… (magnitude)
Chemical property:
describes the type of chemical changes the material tends to undergo. (flammable)
Substances are:
Pure materials that cannot be physically separated into simpler components. Chemical and physical properties are uniform throughout.
Mixtures are 2 or more pure substances. T/F physical processes can separate the mixture into simpler substances
True
Homogenous
Uniform in physical and chemical properties throughout the whole sample. (normal saline)
Heterogenous
distince phase boundaries where chemical or phosical properties change. (italian salad dressing or chia seeds in a beverage.)
T/F: All atoms have protons and electrons and all contain neutrons except for hydrogen.
True
A (atomic Mass number) =Z (atomic number) +N
Is the equation that finds the number of what?
Neutrons
T/F Isotopes are the same element with a different number of neutrons.
True; They have the same atomic number, different mass number.
Dalton’s Atomic Theory:
- ____ are the smallest units of substance
- Compounds are formed by bonding ____ together in a fixed ratio.
- Chemical reactions do not create, destroy, or change ___ into ___of other elements. Chemical reactions cause ____ to recombine into new substances.
atom or atoms.
Dalton’s flaws:
- Not all atoms of an element are identical isotopes.
- Atoms are comprised of even smaller particulars AND nuclear processes convert atoms of one element into atoms of another.
Law of conservation of Mass
components are neither created, nor destroyed. They combine.
Law of Definite Proportions
Different samples of a pure compound always contain the same elements in the same proportion by mass.
example: water= 11.2% Hydrogen and 88.8% Oxygen by mass.
Law of Multiple Proportions
Some elements can combine to give more than one compound.
ex: carbon burned produces both CO2 and CO.
The Periodic Table is organized with rows and vertical groups/families.
The number to protons increases from _____ to _____ (which direction) in the rows.
L to R
The Periodic Table is organized with rows and vertical groups/families.
The elements at the end of each row has a full or empty outer shell of electrons? (R side of the table)
Full
The Periodic Table is organized with rows and vertical groups/families.
Vertical columns of elements share what similarities?
Similar chemical and physical properties.
Elements with nearly full electron shells ___ electrons, anions.
accept
Elements with nearly empty electron shells ____ electrons, Cations.
give up or release
Characteristics of metals include:
- shiny luster
- ductile (can be drawn out into a wire)
- malleable
- good conductors of heat and electricity
- react to form cations by giving away electrons
Characteristics of non-metals include:
- liquids, solids, or gasses
- solids tend to be brittle
- do not conduct
- tend to form anions
Characteristics of metalloids
- intermidiates
- shiny luster
- less malleable and ductile than metals
- conduct electricity but not well-semi conductors
electrolyte
substance that dissolves in water to give a solution conductivity.
