Midterm Exam Flashcards

0
Q

Identify Matter vs. Non-matter?

A
  • Matter: Anything that has mass and occupies space
  • Non-matter: Anything that does not have mass and/or does not occupy space
  • Example: Light, heat, air
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1
Q

What is Chemistry?

A

-The study of the composition of matter and the changes that matter undergoes

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2
Q

List the Steps of the Scientific Method

A
  • Make observations
  • Proposing 2 hypotheses (one is null)
  • Experimentation
  • Form a theory or Scientific Law
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3
Q

Identify the manipulated, responding, and control variables in an experiment

A
  • The manipulated variable in an experiment is the independent variable because it is changed
  • The responding variable is the dependent variable because it reacts depending on the independent variable
  • The control variables in an experiment are the things that are kept constant during an experiment such as heat, an amount of something, etc.
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4
Q

Identify extensive and intensive properties

A
  • Extensive: A property that depends on the amount of matter in a substance (mass, volume, height, length)
  • Intensive: Do not depend on the amount of matter present (malleability, color, boiling point, melting point/freezing point, density)
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5
Q

Compare the properties of solids, liquids, and gases

A
  • Solids: Definite shape, definite volume, particles packed tightly together, almost incompressible, expands when heated
  • Liquids: No definite shape, particles flow freely, fixed volume, almost incompressible, expands when heated
  • Gases: takes shape and volume of container, particles are spread out, easily compressible.
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6
Q

Define physical and chemical change

A
  • Physical change: some properties of a material change, but the composition of the material does not change
  • Chemical change: Any change that results in the formation of a new chemical substance
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7
Q

Provide examples of physical and chemical change

A
  • Physical: Ice melting to become water, water freezing into ice
  • Chemical: mixing sodium and chlorine to made sodium chloride/ salt (NaCl)
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8
Q

Explain why a physical change is reversible or irreversible

A
  • Irreversible: cannot go back to normal (burned paper cannot be turned back into paper)
  • Reversible: cannot go back to normal (ice can be turned back into water)
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9
Q

Explain how chemical reactions can be identified

A
  • Production of Gas
  • Production of precipitate
  • Color change
  • Transfer of Energy
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10
Q

Identify the reactants and products of a chemical change

A
  • Reactant: a substance present at the start of the reaction

- Product: A substance produced in the reaction

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11
Q

Define the law of conservation of mass

A

-Law of conservation of mass: In any physical change or chemical reaction, mass is conserved

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12
Q

Explain how the law of conservation of mass applies to both physical and chemical changes

A
  • Physical change: The product before and after the change will weigh the same (has the same mass).
  • Chemical change: In a chemical reaction, the mass of the products is always equal to the mass of the reactants.
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13
Q

Determine the atomic number and mass of an electron

A
  • Compares the relative masses of all elements to carbon-12. #= weighted average of all isotopes of an element. (It’s units are called atomic mass units)
  • Atomic #= number of protons
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14
Q

Calculate atomic mass of an element from the mass and percent of each isotope

A

-Atomic mass (isotope’s mass x % natural abundance)

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15
Q

Explain how electrons move from one energy level to another

A
  • For electrons to move from a lower energy level to a higher energy level, they absorb energy while emitting light
  • For electrons to move from a higher energy level to a lower energy level, they release energy while emitting light
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16
Q

Rutherford’s Atomic model vs. Bohr Model

A
  • RAM: Only explained a few simple properties of the atom
  • RAM: Could not explain the chemical properties of an element
  • RAM: Could not explain why elements heated to higher temps give off colored light
  • BM: Showed how energy of an atom changes when absorbing or emitting light
  • BM: An electron is only found in specific circular motions, or orbits, around the nucleus
  • BM: Explains that when an atom emits light it is moving from one energy level to another
  • BM: Each orbit has a different energy level and fixed energy
  • Both have something to do with energy
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17
Q

Bohr Model vs. Quantum Mechanical Model

A
  • BM: Only explained the energy in simple atoms like hydrogen
  • QMM: Mathematical equation to describe the behavior of an electron in a hydrogen atom
  • QMM: Does not specify the exact path of an electron around the nucleus
  • QMM: Orbitals use probability to predict a region of space where an electron is found at any given time
  • BM: 2D, QMM: 3D
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18
Q

How to write an electron configureation

A
  • Ways to show
    • Aufbau diagram
    • Standard Electron Configuration
    • Orbital filling diagram
  • Electrons occupy the lower energy levels first (Aufbau principle)
  • To be in the same orbital, electrons must have opposite spin (Pauli exclusion principle)
  • Ever orbital subshell gets 1 electron before receiving another and have parallel spin ( Hund’s rule)
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19
Q

Explain why elements and compounds release different colored light

A
  • The orbitals contain different energy levels when they are transferred
  • Red= lowest
  • Purple= highest
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20
Q

Who created the periodic table?

A
  • Mendeleev

- Based on increasing atomic mass

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21
Q

Identify a substance as a metal, metalloid, or nonmetal

A
  • Metal: shiny, malleable, good conductor of electricity, ductile, mostly solid at room temp
  • Non-Metal: dull, brittle, poor conductor
  • Metalloid: depending on conditions can act like metal or nonmetal, poor conductor
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22
Q

Determine the number of valence electrons in an element

A
  • Look at its group number

- The number of electrons on the outside energy level of an element

23
Q

Alkali Metals

A

-Most Reactive Metals (Group 1 A)

24
Alkaline Metals
- Relatively soft - Harder than alkali metals - Group 2a
25
Halogens
-A nonmetal in group 7A
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Nobles Gases
-An element group in 8a of periodic table
27
Transition metals
-One of the group B metals
28
Inner Transition Metals
-An element in the lanthanide or actinide series
29
Percent Error Formula and Error Formula
- Iexperimental value - true valueI | - IerrorI/accepted value x 100%
30
Si Base Units
- Distance: Meters - Temperature: Kelvin - Density: Kilograms - Volume: Liters - Time: seconds
31
Converting temperature from Kelvin to Celsius and vice versa
- Kelvin= Celsius + 273 | - Celsius= Kelvin -273
32
What is the lowest possible temp on the kelvin scale?
-Absolute 0
33
Tera
-10^12 times larger (T)
34
giga
-10^9 times larger (G)
35
Mega
-10^6 times larger (M)
36
Kilo
10^3 times larger (k)
37
Hecto
10^2 times larger (h)
38
Deka
-10^1 times larger (da)
39
Deci
-10^-1 times smaller (d)
40
centi
-10^-2 times smaller (c)
41
milli
-10^-3 times smaller (m)
42
Micro
-10^-6 times smaller (upside-down h)
43
Nano
-10^-9 times smaller (n)
44
Pico
-10^-12 times smaller (p)
45
Mass, Volume, and Density formulas
- Density= Mass/ volume - Mass= Density x Volume - Volume= Mass/ density
46
Rules for Addition, Subtraction, Multiplication, and Division of Sigfigs
Multiplication and Division: Count # of sigfigs in each #, round to that many sigifgs Addition and Subtraction: Answer rounded to the number with the least number of decimal places
47
What is an atom?
- The smallest particle of an element that retains its identity in a chemical reaction - Mad up of subatomic particles (protons, neutrons, electrons)
48
What makes the atoms of each element unique?
-It's atomic number, aka how many protons it has
49
Explain why Daltons Atomic Theory is true or flase
- True: All matter consists of tiny particles - False: Atoms are indestructible and indivisible - False: Elements are characterized by the mass of their atoms (atoms nuclear charge) - True: When elements react, their atoms combine in whole-number ratios
50
Similarities and Differences between isotopes of the same element
- Similar: # of electrons, # of protons, react the same in chemical reactions - Different: # of neutrons
51
Plumb Pudding Model
- created by Thompson - Positively charged atom with negative particles scattered throughout - No movement - No nucleus - No orbitals
52
Rutherford's Atomic Model
- Discovered through the gold foil experiment - Positively charged nucleus - Electrons orbit nucleus - Movement!
53
Mass number
Protons + Neutrons
54
Number of Neutrons
atomic # - mass Numbers