WGU D425 Intro to Chemistry Study Set | High-
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Questions | Reviewed and well Rationalized |
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How do you distinguish between a pure substance and a mixture?
CORRECT ANSWER:
A pure substance has a fixed chemical composition throughout,
while a mixture consists of two or more substances physically
combined with variable composition.
What is the difference between an intensive and extensive property?
CORRECT ANSWER:
Intensive properties (e.g., density, boiling point) are independent of
the amount of matter; extensive properties (e.g., mass, volume)
depend on the amount of matter present.
How do you determine the state of matter based on temperature
relative to melting and boiling points?
CORRECT ANSWER:
If T < melting point, it is a solid. If melting point < T < boiling point, it is
a liquid. If T > boiling point, it is a gas.
What are the rules for significant figures in multiplication and
division?
CORRECT ANSWER:
,The final answer must have the same number of significant figures as
the measurement with the fewest significant figures.
How do you calculate density?
CORRECT ANSWER:
Density = mass / volume. For irregular objects, volume can be found
via water displacement.
What is the charge, location, and relative mass of a proton?
CORRECT ANSWER:
Positive charge (+1), located in the nucleus, relative mass of
approximately 1 atomic mass unit (amu).
What defines an isotope?
CORRECT ANSWER:
Atoms of the same element (same number of protons) that have
different numbers of neutrons, resulting in different mass numbers.
What is the periodic trend for electronegativity?
CORRECT ANSWER:
Electronegativity increases from left to right across a period and
decreases down a group.
How do you calculate average atomic mass?
CORRECT ANSWER:
Multiply the mass of each isotope by its relative abundance (as a
decimal) and sum the results.
What is the difference between ionic and covalent bonding?
CORRECT ANSWER:
,Ionic bonds involve the transfer of electrons between a metal and a
non-metal; covalent bonds involve the sharing of electrons between
two non-metals.
What is the VSEPR theory used for?
CORRECT ANSWER:
Predicting the 3D molecular geometry of a molecule based on the
repulsion between electron pairs surrounding a central atom.
How do you convert between moles and particles
(atoms/molecules)?
CORRECT ANSWER:
Use Avogadro's number: 1 mole = 6.022 x 10^23 particles.
What is the definition of a limiting reactan t?
CORRECT ANSWER:
The reactant that is completely consumed in a chemical reaction,
thereby limiting the amount of product that can be formed.
How do you calculate percent yield?
CORRECT ANSWER:
Percent Yield = (Actual Yield / Theoretical Yield) x 100%.
What occurs in a redox reaction?
CORRECT ANSWER:
The transfer of electrons between species; one substance is
oxidized (loses electrons) and another is reduced (gains electrons).
What is the difference between a physical and chemical change?
CORRECT ANSWER:
, A physical change alters the form or state of matter without
changing its chemical identity; a chemical change results in the
formation of new substances.
How do you identify a direct relationship on a graph?
CORRECT ANSWER:
A direct relationship shows a straight line passing through the origin
(y = kx).
What is the base SI unit for mass?
CORRECT ANSWER:
The kilogram (kg).
How many valence electrons does an element in Group 17 have?
CORRECT ANSWER:
7 valence electrons.
What is the formula for calculating percent composition?
CORRECT ANSWER:
(Mass of element in formula / Molar mass of compound) x 100%.
What is the purpose of balancing a chemical equation?
CORRECT ANSWER:
To satisfy the Law of Conservation of Mass, ensuring the number of
atoms of each element is the same on both sides of the reaction.
What is the volume of one mole of any gas at STP?
CORRECT ANSWER:
22.4 liters.
How do you identify an oxidizing agent?
CORRECT ANSWER:
Yield Questions &Answers, Exam Prep Guide|
100% Guarantee Pass | Most Highly Tested
Questions | Reviewed and well Rationalized |
Latest Exam and Newest Exam !!!!
How do you distinguish between a pure substance and a mixture?
CORRECT ANSWER:
A pure substance has a fixed chemical composition throughout,
while a mixture consists of two or more substances physically
combined with variable composition.
What is the difference between an intensive and extensive property?
CORRECT ANSWER:
Intensive properties (e.g., density, boiling point) are independent of
the amount of matter; extensive properties (e.g., mass, volume)
depend on the amount of matter present.
How do you determine the state of matter based on temperature
relative to melting and boiling points?
CORRECT ANSWER:
If T < melting point, it is a solid. If melting point < T < boiling point, it is
a liquid. If T > boiling point, it is a gas.
What are the rules for significant figures in multiplication and
division?
CORRECT ANSWER:
,The final answer must have the same number of significant figures as
the measurement with the fewest significant figures.
How do you calculate density?
CORRECT ANSWER:
Density = mass / volume. For irregular objects, volume can be found
via water displacement.
What is the charge, location, and relative mass of a proton?
CORRECT ANSWER:
Positive charge (+1), located in the nucleus, relative mass of
approximately 1 atomic mass unit (amu).
What defines an isotope?
CORRECT ANSWER:
Atoms of the same element (same number of protons) that have
different numbers of neutrons, resulting in different mass numbers.
What is the periodic trend for electronegativity?
CORRECT ANSWER:
Electronegativity increases from left to right across a period and
decreases down a group.
How do you calculate average atomic mass?
CORRECT ANSWER:
Multiply the mass of each isotope by its relative abundance (as a
decimal) and sum the results.
What is the difference between ionic and covalent bonding?
CORRECT ANSWER:
,Ionic bonds involve the transfer of electrons between a metal and a
non-metal; covalent bonds involve the sharing of electrons between
two non-metals.
What is the VSEPR theory used for?
CORRECT ANSWER:
Predicting the 3D molecular geometry of a molecule based on the
repulsion between electron pairs surrounding a central atom.
How do you convert between moles and particles
(atoms/molecules)?
CORRECT ANSWER:
Use Avogadro's number: 1 mole = 6.022 x 10^23 particles.
What is the definition of a limiting reactan t?
CORRECT ANSWER:
The reactant that is completely consumed in a chemical reaction,
thereby limiting the amount of product that can be formed.
How do you calculate percent yield?
CORRECT ANSWER:
Percent Yield = (Actual Yield / Theoretical Yield) x 100%.
What occurs in a redox reaction?
CORRECT ANSWER:
The transfer of electrons between species; one substance is
oxidized (loses electrons) and another is reduced (gains electrons).
What is the difference between a physical and chemical change?
CORRECT ANSWER:
, A physical change alters the form or state of matter without
changing its chemical identity; a chemical change results in the
formation of new substances.
How do you identify a direct relationship on a graph?
CORRECT ANSWER:
A direct relationship shows a straight line passing through the origin
(y = kx).
What is the base SI unit for mass?
CORRECT ANSWER:
The kilogram (kg).
How many valence electrons does an element in Group 17 have?
CORRECT ANSWER:
7 valence electrons.
What is the formula for calculating percent composition?
CORRECT ANSWER:
(Mass of element in formula / Molar mass of compound) x 100%.
What is the purpose of balancing a chemical equation?
CORRECT ANSWER:
To satisfy the Law of Conservation of Mass, ensuring the number of
atoms of each element is the same on both sides of the reaction.
What is the volume of one mole of any gas at STP?
CORRECT ANSWER:
22.4 liters.
How do you identify an oxidizing agent?
CORRECT ANSWER:
