CEM 141 Master Exam 2 Questions with 100%
Complete Solutions
Is there such a thing as a "scientific method?"
no
What do scientists do?
1. ask questions
2. design experiments
3. gather/analyze data and evidence
4. make claims (based on the data/evidence)
5. develop models, explanations, and theories about how/why the universe behaves as it does
How can scientific questions be answered?
-doing experiments
-making observations
-taking measurements
-it must be replicable
What makes something not science?
if an experiment can't be replicated reliably, then it's not science
What do you need when you make a claim?
you need evidence to support it and maybe even a model
What is a scientific model?
,it can be a drawing, graph, diagram, or equation that's physical/mental
What are models used for?
-explain how things happen
-make testable, quantifiable predictions
What do we do with our claims, evidence, and data?
we develop an explanation/scientific theory to help us explain why these things happen
What should scientists aim for?
the most complete set of ideas we can come up with
How do you create a scientific explanation?
1. Claim: the target of your explanation
2. Evidence: data/scientific principle you are using to support your claim
3. Reasoning: connection between your claim and evidence
What is a scientific theory?
the best available explanation of the existing evidence/data/observations
What are the characteristics of a good scientific theory?
-explains how/why something happens
-makes testable predictions
-is falsifiable
-may change over time as new evidence is uncovered
What's the difference between a law and a theory?
,a law describes the phenomenon (so it tells you what happens); a theory explains the
phenomenon (so it tells you why it happens)
Which has atoms in it? Heat, cells, air, or gold?
cells, air, and gold
How big do you think an H atom is?
about 0.1 nanometer
How do we know atoms exist/ what's the evidence?
we can actually "see" them
What are the two methods that allow us to see things at the atomic level?
atomic force microscopy (AFM) and scanning tunneling microscopy (STM)
Where did the original idea for atoms come from?
the Greeks ("atomos"- not to be cut)
What were some of the Greeks most prominent ideas about atoms?
-based on philosophy
-based on the elements
-thought atoms were in constant motion with a "void" between them (Brownian motion)
What was important about how the Greeks theorized atoms were shaped?
it foreshadowed the idea that the atomic/ molecular structure of a substance determines its
observable properties
, What keeps atoms in constant motion?
thermal energy
What differentiates one atom from another?
the number of protons it has
How do we know atoms of certain elements differ from atoms of another?
they have new/ different properties
What's the difference between an atom and a molecule?
an atom is the smallest form of an element and molecules are many atoms bonded together
What's the difference between an element and a compound?
elements are all one type of atom while compounds are many elements combined
What is the smallest unit of an element?
an atom
What are the five key points of Dalton's Atomic Theory?
1. Elements are composed of small, indestructible, indivisible particles called atoms
2. All atoms of an elements are identical and have the same mass and properties
3. Atoms of a given element are different from atoms of other elements
4. Compounds are formed by combos of atoms of two or more elements
5. Chemical reactions are due to the rearrangements, atoms (matter) are neither created nor
destroyed during a reaction
Complete Solutions
Is there such a thing as a "scientific method?"
no
What do scientists do?
1. ask questions
2. design experiments
3. gather/analyze data and evidence
4. make claims (based on the data/evidence)
5. develop models, explanations, and theories about how/why the universe behaves as it does
How can scientific questions be answered?
-doing experiments
-making observations
-taking measurements
-it must be replicable
What makes something not science?
if an experiment can't be replicated reliably, then it's not science
What do you need when you make a claim?
you need evidence to support it and maybe even a model
What is a scientific model?
,it can be a drawing, graph, diagram, or equation that's physical/mental
What are models used for?
-explain how things happen
-make testable, quantifiable predictions
What do we do with our claims, evidence, and data?
we develop an explanation/scientific theory to help us explain why these things happen
What should scientists aim for?
the most complete set of ideas we can come up with
How do you create a scientific explanation?
1. Claim: the target of your explanation
2. Evidence: data/scientific principle you are using to support your claim
3. Reasoning: connection between your claim and evidence
What is a scientific theory?
the best available explanation of the existing evidence/data/observations
What are the characteristics of a good scientific theory?
-explains how/why something happens
-makes testable predictions
-is falsifiable
-may change over time as new evidence is uncovered
What's the difference between a law and a theory?
,a law describes the phenomenon (so it tells you what happens); a theory explains the
phenomenon (so it tells you why it happens)
Which has atoms in it? Heat, cells, air, or gold?
cells, air, and gold
How big do you think an H atom is?
about 0.1 nanometer
How do we know atoms exist/ what's the evidence?
we can actually "see" them
What are the two methods that allow us to see things at the atomic level?
atomic force microscopy (AFM) and scanning tunneling microscopy (STM)
Where did the original idea for atoms come from?
the Greeks ("atomos"- not to be cut)
What were some of the Greeks most prominent ideas about atoms?
-based on philosophy
-based on the elements
-thought atoms were in constant motion with a "void" between them (Brownian motion)
What was important about how the Greeks theorized atoms were shaped?
it foreshadowed the idea that the atomic/ molecular structure of a substance determines its
observable properties
, What keeps atoms in constant motion?
thermal energy
What differentiates one atom from another?
the number of protons it has
How do we know atoms of certain elements differ from atoms of another?
they have new/ different properties
What's the difference between an atom and a molecule?
an atom is the smallest form of an element and molecules are many atoms bonded together
What's the difference between an element and a compound?
elements are all one type of atom while compounds are many elements combined
What is the smallest unit of an element?
an atom
What are the five key points of Dalton's Atomic Theory?
1. Elements are composed of small, indestructible, indivisible particles called atoms
2. All atoms of an elements are identical and have the same mass and properties
3. Atoms of a given element are different from atoms of other elements
4. Compounds are formed by combos of atoms of two or more elements
5. Chemical reactions are due to the rearrangements, atoms (matter) are neither created nor
destroyed during a reaction
