ACS Chemistry 101 & 102 Final Exam Review 44 Questions with Verified Answers,100% CORRECT

ACS Chemistry 101 & 102 Final Exam Review 44 Questions with Verified Answers What is the difference between a homogeneous and heterogeneous mixture? Can they be separated? - CORRECT ANSWER A homogeneous mixture is a uniform composition throughout whereas a heterogeneous mixture has other substances. They can be separated but through physical processes. What is the difference between a physical and chemical property? Physical vs chemical change? - CORRECT ANSWER A physical property is one that can be determined without changing the identity of the matter. A physical change is where the identity of the matter does not change. A chemical property is a property (only determined as a result of a chemical change or chemical process) in which the original substance is converted to a different substance. Whats the difference between an extensive property and an intensive property? - CORRECT ANSWER An extensive property is dependent on the amount of matter. An intensive property is independent of the amount of matter. List the SI units in chemistry. Derived Units? - CORRECT ANSWER 1. Mass - Kilogram (kg) 2. Temperature - Kelvin (K) 3. Time - Seconds (s) 4. Length - Meter (m) 5. Amount of substance - Moles (mol) 6. Electric Current - Ampere (A) Derived Units: Density (g/mL) and Volume (mL or cm³) Whats the difference between accuracy and precision? - CORRECT ANSWER Accuracy refers to how close measured numbers are to the true value. Precision refers to how close measured numbers are to one another. What are the different types of radioactivity atoms give off? - CORRECT ANSWER Alpha rays composed of positively charged a particles. Beta rays are composed of negatively charged B particles. Gamma rays composed of neutral y rays or gamma particles. What is Z vs A representing an atom? - CORRECT ANSWER Atomic number (Z) is the number of protons in the nucleus of an atom. Mass number (A) is the sum of protons and neutrons in the nucleus. This sum is referred to as NUCLEONS. A=mass of atom Z=identity of atom Whats an Isotope? - CORRECT ANSWER Atoms with the same atomic number (Z) but different mass numbers (A). What are the "magic numbers" and whats their significance? - CORRECT ANSWER The magic numbers are 2, 8, 20, 50, 82 and 126. They represent the protons or neutrons that make up an isotope that mean they are the most nuclear stable. What pattern describes the most unstable vs most stable isotope? - CORRECT ANSWER In order of increasing stability. 1. An odd number of protons and neutrons means least stable. 2. Protons = odd & neutrons = even (less stable than) protons = even & neutrons = odd 3. An even number of both protons and neutrons means the most stable. What is 1 amu equal to? Is the mass listed on the periodic table in grams or amu? - CORRECT ANSWER The numbers listed on the periodic table are in amu. 1 amu = 1.6605 x 10⁻²⁴ g. How do you calculate average atomic weight? - CORRECT ANSWER Average atomic weight is determined through (fraction 1 x element 1) + (fraction 2 x element 2) + (fraction n x element n) = average atomic mass. What is the difference between periods and families on the periodic table? - CORRECT ANSWER A period is horizontal rows of increasing atomic number. A family is vertical columns of increasing atomic number as well. What are the properties of metals? Nonmentals? Metalloids? - CORRECT ANSWER A metal is a good conductor of heat and electricity with a tendency to lose electrons. Metals are lustrous malleable and ductile. They also have low ionization energy forming cations. A nonmetal is a poor conductor of heat and electricity with a tendency to gain electrons. Nonmetals vary in color, lack shiny appearances, and brittle. Nonmetals have high electron affinities forming anions. A metalloid is an element with properties of both a metal and a nonmental. What is potential, kinetic, chemical, and electrostatic energy - CORRECT ANSWER Potential is energy possessed by an object due to its position. Kinetic is energy possessed by an object due to its motion. Chemical energy is energy stored within the structural units of chemical substances. Electrostatic energy is potential energy that results from the interaction of charged particles. What is one Joule equal to? One newton? - CORRECT ANSWER 1 J = 1 N * m 1 N = 1 kg * m/s² What is the speed of light constant? What is the formula relating speed wavelength and frequency of a wave? - CORRECT ANSWER c=lamda*V lamda is wavelength, v is frequency and c is speed. The speed of light constant is 3.0 x 10⁸. Which determines the higher energy frequency or wavelength? Which visible light wave is closer to the higher energy side of the spectrum? - CORRECT ANSWER Frequency determines the higher energy wave. Violet is closer to gamma rays which are the higher energy waves whereas red is closer to the radio waves which are the lower energy waves. What is the equation relating the energy E of a single quantum energy, the frequency of radiation and plancks constant? - CORRECT ANSWER Planck's constant is 6.63 x 10⁻³⁴ J*s. The equation is E=hv where h is plancks constant, v is frequency and E is the energy of a single quantum energy. What is the type of spectra emitted by an electron in the excited state? Ground state? - CORRECT ANSWER Emission spectra for excited, and absorption spectra for ground state. Ground state is the lowest energy state of an atom, and an excited state is any state higher than the ground state. What is the de Broglie wavelength and how is it calculated? - CORRECT ANSWER The de Broglie wavelength is calculated from plancks constant divided by its mass and velocity. What is Heisenberg's Uncertainty Principle? - CORRECT ANSWER Heisenberg's Uncertainty principle states that it is impossible to know simultaneously both the momentum p and the position x of a particle with certainty. What is the relationship between light intensity and electrons emitted as well as frequency of light and kinetic energy of ejected electrons? - CORRECT ANSWER A greater light intensity means a greater number of electrons emitted. A higher frequency of light means a higher kinetic energy of ejected electrons. What is the relationship between the frequency of a vibration, length of wavelength, and the number of nodes in a wave? - CORRECT ANSWER The greater the frequency, the smaller the wavelength, and the higher the number of nodes. What are the four quantum numbers that describe the arrangement of electrons? - CORRECT ANSWER Principal quantum number (n) designates the size of the orbital (energy level). Angular momentum quantum (l) number describes the shape of the atomic orbital, ex: l=0 is an s orbital and so forth. Magnetic quantum number (ml) describes the orientation of the orbital in space (where the electron is in the _ _ _ orbital), ex: ml for a p orbital can be -1, 0, 1. Electron spin quantum number is the positive or negative spin of an electron, ex: 1/2 or -1/2. What is the difference between diamagnetic and paramagnetic? - CORRECT ANSWER Diamagnetic means all the electrons have a pair in the highest orbital. Paramagnetic means no electrons have a pair in the highest orbital. How can you tell which orbital has the highest amount of energy? - CORRECT ANSWER The outermost orbital has the highest amount of energy. The higher the n the higher the energy. Orbitals with the same principal quantum number n all have the same energy. What is the Pauli Exclusion Principle? - CORRECT ANSWER The Pauli exclusion principle states no two electrons in an atom can have the same four quantum numbers. Two electrons can't have the same spin. What is the Aufbau Principle? - CORRECT ANSWER The Aufbau principle states how to add electrons to orbitals. What is Hund's Rule? - CORRECT ANSWER Hund's rule is where each empty orbital must be filled before having another electron added. What is effective nuclear charge (Zeff)? - CORRECT ANSWER The actual magnitude of positive charge from a nucleus felt by an electron. What is the general trend for atomic radius on the periodic table? - CORRECT ANSWER Atomic radius decreases from left to right and increases from top to bottom. What is the general trend for ionization energy on the periodic table? - CORRECT ANSWER Ionization energy increases from left to right across a period. Ionization energy decreases from top to bottom. Whats the difference between electron affinity and electronegativity? - CORRECT ANSWER Electron affinity is the energy released when an atom in the gas phase accepts an electron. Electronegativity is the ability of an atom to draw bonding electrons to itself. Whats the general trend for electron affinity? - CORRECT ANSWER Electron affinity increases from left to right across a period. Whats the general trend for metallic character? - CORRECT ANSWER Metallic character increases from top to bottom and decreases from left to right. Whats a diagonal relationship? - CORRECT ANSWER A diagonal relationship refers to similarities between pairs of elements in different groups and periods of the periodic table through a diagonal line. Which has the biggest jump in energy from n=1 to n=2 or n=2 to n=3? - CORRECT ANSWER n=1 to n=2 because it requires the most energy, it has the largest step. What is deuterium and how is it different from hydrogen? - CORRECT ANSWER Deuterium is one of the stable isotopes of hydrogen, the nucleus (deuteron) contains one proton and one neutron whereas the common hydrogen isotope (protium) has no neutron in the nucleus. Whats an isomer, allotrope and polymer? - CORRECT ANSWER An isomer is a chemical compound with the same formula but different arrangement of atoms and different properties. An allotrope is a different form or state in which an element can exist. I.E. graphite and diamond. A polymer is a molecular structure consisting of a large number of similar molecules bonded together. What confirms the existence of discrete (quantized) energy levels in an atom? - CORRECT ANSWER The atomic line spectra. What statement would describe the mass and volume composition of an atom? - CORRECT ANSWER Protons and neutrons have most of the mass but occupy very little volume of the atom. What does a normal melting/boiling point mean for pressure? - CORRECT ANSWER A normal melting/boiling point means the solid and liquid or liquid and gas are at equilibrium AT STANDARD PRESSURE (760 mmhg = 1 atm = 101.3 kPA). What happens to the boiling point when two different but pure substances are mixed? - CORRECT ANSWER The boiling point of the new mixture goes down even if the original pure substances have the same boiling point. However if the two samples are from the same substance the boiling point would stay the same.