Chem Midterm Flashcards
What are atoms?
Very small particles that are the fundamental building blocks of matter
What are molecules?
Tiny particles that are composed of atoms & can consist of two or more atoms bonded together.
What do atoms form?
Molecules
What are chemical bonds?
The attachments that hold atoms together that can be ionic, covalent, or metallic
__________ are tiny particles that compose all common matter.
Atoms
What do water molecules consist of?
3 atoms bonded together:
-1 oxygen
-2 hydrogen
What does chemistry explain?
The properties and behavior of chemicals in the molecules that compose them
Who said “all things are made of atoms “?
Richard Feynman
What is the scientific method?
The way that scientists learn about the natural world. It involves observations, laws, hypotheses, theories, and experimentation.
What is the first step of the scientific method?
Observation
What is observation?
An observation must measure or describe something about the physical world
What is chemistry?
The science that tries to understand how matter behaves by studying how atoms and molecules behave
What are observations?
Observations involve measuring or observing some aspect of nature
What are hypotheses?
Hypotheses are tentative interpretations of the observations
What are laws?
Laws summarize the results of a large number of observations
What are theories?
Models that explain and give the underlying causes for observations and laws
What must hypothesis, laws, and theories be tested and validated by?
Experiment
What happens if I hypotheses are not confirmed?
They are revised and tested through further experimentation
Can some observations be made with the naked eye?
Yes
What do observations usually involve?
The measurement or description of some aspect of the physical world
What is the mass of an object measured by?
By the quantity of matter within it
Who made an observation about the physical world that measured the property of mass in the process of combustion?
Antoine Lavoisier
What is a hypothesis?
An explanation of the observations
What does it mean when a good hypothesis is falsifiable?
It means that further testing has the potential to prove it wrong
How are hypotheses tested?
By experiments
What are experiments?
Highly controlled observations designed to validate or invalidate hypotheses
What do a number of similar observations lead to the development of?
A scientific law
What is a scientific law?
A brief statement that synthesizes past observations and predicts future ones
Who developed the law of conservation of mass?
Antoine Lavoisier
What is the law of conservation of mass?
In a chemical reaction, matter is neither created nor destroyed
What do one or more well established hypotheses for the basis of?
A scientific theory
What are scientific theories?
Models of the way nature is
What is the order of the scientific method?
Observations, hypothesis, theory, experiment
What are the key characteristics of the scientific method?
Observation, the formulation of hypotheses, the testing of hypotheses by experiment, and the formulation of laws and theories
Who discovered penicillin?
Alexander Fleming
True or false: the Greek philosophers used observation and experimentation to understand the world?
False
True or False: molecules are responsible for scattering light which causes the colors of the sunset?
True
True or False: an established theory is the pinnacle of scientific theory?
True
Which of the following statements about soda pop is FALSE?
-The carbon dioxide is forced to mix with the water by the presence of sugars.
-All of the above statements are true.
-Soda pop is a chemical mixture of mostly sugar, water, and carbon dioxide.
-The molecules important to fizzing are carbon dioxide and water.
-When a can is opened, the pressure release allows carbon dioxide to form bubbles.
The carbon dioxide is forced to mix with the water by the presence of sugars
Which of the following would be considered a theory?
-Hot air rises
-Helium balloons float because helium is less dense than air
-Gasoline has a very strong odor
-Glass is fragile
Helium balloons float because helium is less dense than air
Who discovered atomic theory?
John Dalton
True or False: The decimal number 0.0000010 expressed in scientific notation is 1.0 x 10^6?
False
True or False: Exact numbers have an unlimited number of significant figures?
True
True or False: In multiplication and division calculations, the answer will have the same number of decimal places as the number carrying the fewest decimal places?
False
True or False: A solution map is section near the back of the textbook that provides the answers to assigned problems?
False
Suppose a thermometer has marks at every one-degree increment and the mercury level on the thermometer is exactly between 25 and 26 degrees Celsius marks. What should we properly report the temperature measurement as?
25.5 Degrees Celsius
How many inches are in 2.80 ft?
33.6
What is the correct decimal representation of 6.453 x 10^3?
6,453
A 12-oz soda pop costs eighty-nine cents. A 2.00 L bottle of the same variety of soda pop costs $2.29. How many times more expensive is it to buy the 12-oz can of pop compared to buying it in a 2.00 L bottle? (1.00 L=1.057 quart and 1 quart contains 32 oz.)
2.2
What is the volume of a cube with dimensions 11.0 cm x 11.0 cm x 11.0 cm in m^3?
1.33 x 10^-3
What is the correct prefix for the multiplier 1,000?
-micoro
-nano
-none of the above
-mega
-milli
none of the above
There are exactly 2.54 cm in 1 in. When using this conversion factor, how many significant figures are you limited to?
infinite number of significant figures
Determine the answer to the following equation with the correct number of significant figures: 106/9.02 x 1.9=?
22
The common English unit in which the speed of an automobile is expressed is miles/hr. What is the set base SI units for speed?
m/s
A plastic block has dimensions of 2.2cm x 3.0cm x 1.5cm and a mass of 12.4 grams. Will the block float in water and why?
No, because the density of the block is 1.3 g/mL which is greater than the density of water of approx 1 g/mL
True or False: Skim milk is a heterogeneous mixture?
False
True or False: In a chemical reaction, the substances present after the chemical change are called reactants?
False
True or False: Solids have indefinite shape and volume?
False
True or False: The energy of position is called kinetic energy?
False
True or False: An example of a chemical change is burning a wood log to give a pile of ashes?
True
How would you classify salt water?
mixture-homogeneous
What is the value of 98 deg F in units of deg C?
37
What is the boiling point of water?
-212 F
-0 C
-373 K
1 and 3 only
All of the following can be considered physical properties EXCEPT?:
-color
-boiling point
-flammability
-taste
-density
flammability
True or False: The elements within a group on the periodic table tend to have similar properties?
True
True or False: The charges on electrons and neutrons cancel each other to give neutral atoms?
False
True or False: Metals are located on the left side of the periodic table?
True
True or False: If two atoms each contain different numbers of protons, the atoms must be from different elements?
True
True or False: A positive charge attracts negative charges and repels other positive charges?
True
What are Group 8A elements also called?
noble gases
Where are metals located where on the periodic table?
left side
When an atom loses an electron, the resulting particle is called?
a cation
Which of the following is a main-group element?
-Cs
-none of the above
-Co
-Cu
-Ce
Cs
How many electrons would be in a -2 charged anion of sulfur?
18
True or False: a cation forms when an atom gains an electron?
False
True or False: protons and electrons each have a mass of 1 amu?
False
True or False: the nucleus of an atom is a very small, dense region that contains over 99.9% of the atomic mass?
True
True or False: the charges on electrons and neutrons cancel each other to give neutral atoms?
False
True or False: the elements within a group on the periodic table tend to have similar properties?
True
What are Group 2A elements also called?
alkaline earth metals
What is the atomic symbol for tin?
Sn
What are Group 1A elements also called?
alkali metals
What is the atomic symbol for silver?
Ag
What is the correct formula for a potassium ion with 18 electrons?
K+
True or False: liquids have definite volume and indefinite shape?
True
True or False: air is a pure substance?
False
True or False: when a temperature in degrees Celsius is converted to Kelvins, the Kelvin value will have the same number of decimal places as the Celsius value?
True
True or False: when a chemical “cold pack” is activated, the chemical reactants absorb heat from the surroundings?
True
True or False: Absolute zero is equivalent to a temperature of -273 K?
False
How would you classify sugar?
pure substance-compound
A pure substance is?
composed of only one type of atom or molecule
Which of the following items is a mixture?:
-sugar
-brass
-helium
-water
-none of the above
brass
If you hold a solid piece of pure gallium metal in your hand, your body heat will melt the gallium into its liquid form. This illustrates what?
physical change
What does the subshell letter specify?
the 3-D shape of the orbital
Which orbital would the electron of a ground state hydrogen atom accupy?
1s
How many subshells are there in the n=2 principle shell?
2
Which of the following atoms is the smallest?
-B
-O
-Be
-Li
-Ne
Ne
True or False: the elements will lose or gain electrons as needed to have an electron configuration that matches a noble gas?
True
True or False: the Pauli exclusion principle states that orbitals may hold no more than two electrons of identical spins?
False
True or False: the element manganese (symbol = Mn) has 5 valence electrons?
False
True or False: the correct electron configuration for magnesium is: 1s^2 2s^2 2p^6 3s^3
False
True or False: the ground state is when an electron in an atom is excited into the lowest possible vacant orbital?
False
How many electrons are unpaired in the orbitals of nitrogen?
3
Which subshell letter corresponds to a spherical orbital?
s
Which of the following atoms is the largest?
-K
-Na
-Cs
-Rb
-Li
Cs
True or False: transition metal elements always contain at least one “d” block electron?
True
True or False: Bromine has 28 core electrons?
True
What is the angle between electron groups in the tetrahedral geometry?
109.5 degrees
What is the molecular geometry if you have 4 single bonds around the central atom?
tetrahedral
What is the molecular geometry of carbon dioxide, CO2?
linear
What is the molecular geomtry if you have a double bond, a single bond, and 1 lone pair around the central atom?
bent
The Lewis model predicts that the formula for a compound between fluorine and calcium is?
CaF2
True or False: water and oil do not mix because water molecules are nonpolar and molecules that compose oil are generally polar?
False
True or False: when calculating the number of electrons for the Lewis structure of a polyatomic ion, subtract one electron for each negative charge?
False
True or False: Lewis structures only use the valence electrons in determining the bonding?
True
True or False: a chemical bond is classified as a covalent bond if it involves the transfer of electrons?
False
What is the molecular geometry of NH4+?
tetrahedral
What is the angle between electron groups in the trigonal planar electron geometry?
120 degrees
What is the molecular geometry of PH3?
trigonal pyramid
True or False: the Lewis structure of water has two sets of lone pair electrons?
True
True or False: a chemical bond is classified as a covalent bond if it involves the transfer of electrons?
False
True or False: when you have 2 electron groups and none are lone pairs, the molecular geometry is linear?
True
