ACS CHEMISTRY 101 & 102 FINAL
EXAM REVIEW
What is the difference between a homogeneous and heterogeneous mixture?
Can they be separated? - Correct Answers -A homogeneous mixture is a uniform
composition throughout whereas a heterogeneous mixture has other substances.
They can be separated but through physical processes.
What is the difference between a physical and chemical property?
Physical vs chemical change? - Correct Answers -A physical property is one that can be
determined without changing the identity of the matter. A physical change is where the
identity of the matter does not change.
A chemical property is a property (only determined as a result of a chemical change or
chemical process) in which the original substance is converted to a different substance.
Whats the difference between an extensive property and an intensive property? -
Correct Answers -An extensive property is dependent on the amount of matter.
An intensive property is independent of the amount of matter.
List the SI units in chemistry.
Derived Units? - Correct Answers -1. Mass - Kilogram (kg)
2. Temperature - Kelvin (K)
3. Time - Seconds (s)
4. Length - Meter (m)
5. Amount of substance - Moles (mol)
6. Electric Current - Ampere (A)
Derived Units:
Density (g/mL) and Volume (mL or cm³)
Whats the difference between accuracy and precision? - Correct Answers -Accuracy
refers to how close measured numbers are to the true value.
, Precision refers to how close measured numbers are to one another.
What are the different types of radioactivity atoms give off? - Correct Answers -Alpha
rays composed of positively charged a particles.
Beta rays are composed of negatively charged B particles.
Gamma rays composed of neutral y rays or gamma particles.
What is Z vs A representing an atom? - Correct Answers -Atomic number (Z) is the
number of protons in the nucleus of an atom.
Mass number (A) is the sum of protons and neutrons in the nucleus. This sum is
referred to as NUCLEONS.
A=mass of atom
Z=identity of atom
Whats an Isotope? - Correct Answers -Atoms with the same atomic number (Z) but
different mass numbers (A).
What are the "magic numbers" and whats their significance? - Correct Answers -The
magic numbers are 2, 8, 20, 50, 82 and 126. They represent the protons or neutrons
that make up an isotope that mean they are the most nuclear stable.
What pattern describes the most unstable vs most stable isotope? - Correct Answers -In
order of increasing stability.
1. An odd number of protons and neutrons means least stable.
2. Protons = odd & neutrons = even (less stable than) protons = even & neutrons = odd
3. An even number of both protons and neutrons means the most stable.
What is 1 amu equal to? Is the mass listed on the periodic table in grams or amu? -
Correct Answers -The numbers listed on the periodic table are in amu.
1 amu = 1.6605 x 10⁻²⁴ g.
How do you calculate average atomic weight? - Correct Answers -Average atomic
weight is determined through (fraction 1 x element 1) + (fraction 2 x element 2) +
(fraction n x element n) = average atomic mass.
What is the difference between periods and families on the periodic table? - Correct
Answers -A period is horizontal rows of increasing atomic number.
A family is vertical columns of increasing atomic number as well.
EXAM REVIEW
What is the difference between a homogeneous and heterogeneous mixture?
Can they be separated? - Correct Answers -A homogeneous mixture is a uniform
composition throughout whereas a heterogeneous mixture has other substances.
They can be separated but through physical processes.
What is the difference between a physical and chemical property?
Physical vs chemical change? - Correct Answers -A physical property is one that can be
determined without changing the identity of the matter. A physical change is where the
identity of the matter does not change.
A chemical property is a property (only determined as a result of a chemical change or
chemical process) in which the original substance is converted to a different substance.
Whats the difference between an extensive property and an intensive property? -
Correct Answers -An extensive property is dependent on the amount of matter.
An intensive property is independent of the amount of matter.
List the SI units in chemistry.
Derived Units? - Correct Answers -1. Mass - Kilogram (kg)
2. Temperature - Kelvin (K)
3. Time - Seconds (s)
4. Length - Meter (m)
5. Amount of substance - Moles (mol)
6. Electric Current - Ampere (A)
Derived Units:
Density (g/mL) and Volume (mL or cm³)
Whats the difference between accuracy and precision? - Correct Answers -Accuracy
refers to how close measured numbers are to the true value.
, Precision refers to how close measured numbers are to one another.
What are the different types of radioactivity atoms give off? - Correct Answers -Alpha
rays composed of positively charged a particles.
Beta rays are composed of negatively charged B particles.
Gamma rays composed of neutral y rays or gamma particles.
What is Z vs A representing an atom? - Correct Answers -Atomic number (Z) is the
number of protons in the nucleus of an atom.
Mass number (A) is the sum of protons and neutrons in the nucleus. This sum is
referred to as NUCLEONS.
A=mass of atom
Z=identity of atom
Whats an Isotope? - Correct Answers -Atoms with the same atomic number (Z) but
different mass numbers (A).
What are the "magic numbers" and whats their significance? - Correct Answers -The
magic numbers are 2, 8, 20, 50, 82 and 126. They represent the protons or neutrons
that make up an isotope that mean they are the most nuclear stable.
What pattern describes the most unstable vs most stable isotope? - Correct Answers -In
order of increasing stability.
1. An odd number of protons and neutrons means least stable.
2. Protons = odd & neutrons = even (less stable than) protons = even & neutrons = odd
3. An even number of both protons and neutrons means the most stable.
What is 1 amu equal to? Is the mass listed on the periodic table in grams or amu? -
Correct Answers -The numbers listed on the periodic table are in amu.
1 amu = 1.6605 x 10⁻²⁴ g.
How do you calculate average atomic weight? - Correct Answers -Average atomic
weight is determined through (fraction 1 x element 1) + (fraction 2 x element 2) +
(fraction n x element n) = average atomic mass.
What is the difference between periods and families on the periodic table? - Correct
Answers -A period is horizontal rows of increasing atomic number.
A family is vertical columns of increasing atomic number as well.
