Quiz
CEM 141 Final Exam Practice
Create a free account to finish this quiz
Save your progress and see your final score.
Already have an account? Sign in
Questions in this quiz (20)
1Which of the following statements about scientific theories are false?
- AMust be revised when new conflicting evidence is presented
- Bdo not require supporting evidence
- Cdo not change once established
- Ddon't require supporting evidence and dont change once established
- Emust be testable and must be revised when new conflicting evidence is presented
2Which of the following is a law?
- Athe attraction between two masses is proportional to the product of their masses and indirectly proportional to the square of the distance between them
- Bthe properties of matter can be explained by understanding that matter is composed of atoms that interact and move in various predictable ways
- Ccarbon has 6 protons
- Dif I heat up this substance, it will decompose
3Two elements, hydrogen and chlorine, both exist as diatomic molecules. Which element do you predict to have the higher melting point and why?
- AH2 would have the higher melting point because it has a smaller electron cloud that is more easily polarized.
- BH2 would have the higher melting point because the gravitational force between hydrogen molecules is stronger than between chlorine molecule
- CCl2 would have the higher melting point because the covalent bond within the chlorine molecule is stronger than the covalent bond within the hydrogen molecule
- DCl2 would have the higher melting point because it has a larger electron cloud that is more easily polarized
- EThe melting points of both elements would be the same because hydrogen and chlorine both exist as diatomic elements
4Oxygen (O2) is a lquid at 70K and a gas at 250K. Select the best molecular-level explanation to support this claim.
- ALondon disperson forces become weaker as the temperature increases. As a result, london dispersion forces at 250 K are easier to overcome which allows the oxygen molecules to form a gas
- Bthe boiling point of oxygen is 90K and the melting point is 54K, so oxygen must be a liquid at 70K and a gas at all temperatures above 90K
- CAt 70K oxygen molecules, don't have enough Kinetic energy to totally overcome attractive london dispersion forces, whereas at 250K they do.
- DA temperature of 250K is required to break the bonds between oxygen atoms in order to form the gas.
5Why do London dispersion forces exist between atoms of helium?
- Athe electron cloud on the He atom fluctuates, creating an instantaneous dipole
- BAll He atoms have permanent dipoles because the electron cloud is never distributed evenly around the nucleus
- CBecause He atoms cannot form covalent bonds
- Dthe electron cloud on the He atom fluctuates, creating an instantaneous dipole and the dipole of one atom is attracted to the dipole of another atom
- Eall He atoms have permanent dipoles because the electron cloud is never distributed evenly around the nucleus and because He connot form covalent bonds
- FAll He atoms have permanent dipoles because the electron cloud is never distributed evenly around the nucleus and the dipole of one atom is attracted to the dipole of another atom
6Which contains the largest total number of molecules?
- A1 mole of CH4
- B1 mole of H2O
- C1 mole of H2
- Dthey all contain the same number of molecules
7How many moles of carbon dioxide are formed when 60 g of glucose reacts with an excess of oxygen?
C6H12O6 --> 6 CO2 + 6 H2O- A0.33 moles
- B1.0 moles
- C2.0 moles
- D3.0 moles
- E6.0 moles
8When 60 g of glucose reacts with 90g of oxygen, which reactant is the limiting reagent and why?
C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O- Aglucose, because its quantity will produce less carbon dioxide
- Bglucose, because there are fewer moles of glucose than moles of oxygen
- Cglucose, because the mass of glucose avialable is smaller
- DOxygen, becasue its quantity will produce less carbon dioxide
- Eoxygen, because it takes more moles of oxygen than glucose to form carbon dioxide
9Consider the evidence: the result of the double slit experiment is an interference pattern- a series of bright and dark lines on a screen. Choose the correct claim and reasoning that this evidence supports
- AClaim: light is a wave.
Reasoning: when a beam of light passes through two small slits, the two resulting waves interfere with each other. Waves of light interfere constructiveky when they arrive in-phase and destructively when they arrive out-of-phase causing an interference pattern to emerge - BClaim: Light is a wave
Reasoning: photons of light collide with each other after passing through the slits, causing an interference pattern to emerge. - CClaim: light is a particle
Reasoning: when a beam of light passes through two small slits, the two resulting waves interfere with each other. waves of light interfere constructively when they arrive in-phase and destructively when they arrive out-of-phase causing an interference pattern to emerge. - DClaim: light is a particle
Reasoning: photons of light collide with each other after passing through the slits, causing an interference pattern to emerge
- AClaim: light is a wave.
10which of the follwing statements is/ are true about the threshold frequency from the photoelectric affect experiment?
- AIt is the frequency needed for an electron to move from a low energy level to a higher energy level within the electron cloud
- Bit is the frequency needed to completely remove an electron from the electron cloud.
- CThe threshold frequency is related to how tightly a valence electron is attracted to the nucleus
- Dit is a frequency needed for a electron to move from a low energy level to a higher energy level within the electron cloud and the threshold frequency is related to how tightly a valence electron is attracted to the nucleus
- Eit is the frequency needed to completely remove an electron from the electron cloud and the threshold frequency is related to hpw tightly valence electron is attracted to the nucleus.
11The hydrogen emission spectrum can be explained using current models of the atom because
- Acurrent models define specific energy gaps between alectron energy levels
- Bcurrent models define the position and the energy of the electron very accurately
- Ccurrent models postulate that the electron is circling the nucleus like a planet around the sun
- Dthe hydrogen emission spectrum cannot be explained by using current models of the atom
12which would experience a higher effective nuclear charge and why?
- Aa valence elctron in a flourine atom because the number of protons in the nucleus that are not shielded by core electrons is greater
- Ba valence electron in a chlorine atom because the number of core elctrons is greater
- Ca valence electron in a chlorine atom because the increase in the number of protins is cancelled out by an increase in the number of core electrons.
- Dthey experience the same effective nuclear charge because the increase in the number of protons is cancelled out by an increase in the number of core electrons
- Ethey experience the same effective nuclear charge because the number of protons in the nucleus that are not shielded by core electrons is greater
13what is the best explanation for why graphite is slippery while diamond is not?
- Athe covalent bonds in graphite are weaker than the covalent bonds in a diamond.
- Bthe bonding in graphite and diamond is different.
- Celectrons in graphite are delocalized, but the electrons in diamond are not.
- Dsheets of graphite are held together by weak LDF's while only covalent bonds exist within diamond.
14the hybridization of the carbon atom identified by the arrow is
C2OH4 (structure)- Asp
- Bdsp
- Csp^2
- Ddsp^3
- Esp^3
15the molecular shape around the carbon identified by the arrow is
C2OH4 (structure)- Alinear
- Bbent
- Ctriginal planar
- Dtetrahedral
- Etriagonal bipyramidal
16the carbon highlighted by the arrow forms (carbon that has the double bond with oxygen)
C2OH4 (structure)- A1 sigma bond and 2 pi bonds
- B2 sigma bonds and 1 pi bond
- C2 sigma bonds and 2 pi bonds
- D3 sigma bonds and 1 pi bond
- E4 sigma bonds
17which statement best represents the trend in electronegativity of elements moving down a column in the periodic table, and what is the cause of the trend?
- Athe effective nuclear charge is the same for all elements in a column
- Blarger atoms can attract electrons in a bond bond more strongly
- Cthe increase in effective nuclear charge increases electrostatic attraction between the nucleus and electrons in bonds
- Dthe decrease in the effective nuclear charge reduces the electrostatic forces between the nucleus and bonding electrons
- Ethe increasing size of atoms reduces the strength of electrostatic attraction between the nucleus and electrons in bonds
18the lewis structure for sulfur dioxide is
- Aalways nonpolar
- Balways polar
- Csometimes polar and sometimes nonpolar depending on how the oxygen atoms are arranged around the sulfur
19look at the Lewis structure for sulfur dioxide. what is the electron center geometry around the sulfur?
- Alinear
- Bbent
- Ctrigonal planar
- Dtetrahedral
- Etrigonal pyramidal
20rank the relative melting points for the following substances from lowest to highest?
1. NaCl
2. KCl
3. Cl2- A1< 3< 2
- B3< 1< 2
- C2< 3< 1
- D1< 2< 3
- E3< 2< 1
- F2< 1< 3
Information
- Description
- questions I previously got wrong
- Author
- Madison VanRiper
- Language
- English
- Views
- 26
- Rating
- No ratings yet Rate this quiz