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

Download ACS Chemistry 101 & 102 Final Exam Review 44 Questions with Verified Answers,100% CORRECT and more Exams Chemistry in PDF only on Docsity! 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 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.