CEM 141 MSU Final Exam Questions With Complete Solutions

CEM 141 MSU Final Exam Questions With Complete Solutions Consider the following statement: "A nitrogen molecule is made up of the same type of atoms." Is this statement true or false and why? I. True II. False III. An element is made up of one type of atom. Nitrogen is an element that exists as diatomic molecules. IV. Nitrogen is a compound that exists as diatomic molecules. Compounds are made of different types of atoms. V. Nitrogen is an element and therefore must exist as separate atoms and not molecules. - ANSWER -True because an element is made up of one type of atom. Nitrogen is an element that exists as diatomic molecules. Why does the potential energy increase as two xenon atoms move extremely close together? a. Because the kinetic energy decreases as the atoms slow down. b. Because the electrostatic attractive force from the instantaneous dipoles is dominant. c. Because the repulsive force between the overlapping electron clouds is dominant. d. Because there is more potential energy than kinetic energy when the atoms are close together. - ANSWER -Because the repulsive force between the overlapping electron clouds is dominant Which statement best describes the forces that exist between helium atoms in the solid state? a. The electron cloud on one helium atom is attracted to the electron cloud on the other atom. b. The nucleus of one helium atom is repelled by the nucleus of the neighboring atom. c. The helium atoms share electrons, forming a bond. d. The partial positive end of one atom's instantaneous dipole attracts the partial negative end of the neighboring atom's induced dipole. e. Both atoms have mass, so they are attracted to each other by gravitational forces. - ANSWER -The partial positive end of one atom's instantaneous dipole attracts the partial negative end of the neighboring atom's induced dipole. When a covalent bond is formed between two nitrogen atoms: I. Energy is absorbed II. Energy is released III. A molecule is formed IV. The nitrogen changes from the gaseous to the liquid state. - ANSWER -Energy is released A molecule is formed The London dispersion force between two neon atoms compared to the London dispersion force between two argon atoms where both systems are the most stable is: I. The same II. Stronger III. Weaker Because: IV. They are both noble gasses V. Neon has a smaller electron cloud, therefore there will be a smaller separation of charge resulting in a weaker force. VI. Neon has a smaller electron cloud, therefore there will be a larger separation of charge resulting in a stronger force. - ANSWER -Weaker because neon has a smaller electron cloud, therefore there will be a smaller separation of charge resulting in a weaker force. Is the following statement true or false? When chlorine freezes, LDFs are formed. This statement is: I. True II. False Because: III. When a substance freezes, covalent bonds are formed IV. There are LDFs in both the solid state and the liquid state, but more in the solid state. V. There are LDFs in the solid state, but not in the liquid state - ANSWER -True because there are LDFs in both the solid state and the liquid state, but more in a solid state Which do you predict to have a higher boiling point, fluorine (F2) or neon (Ne) and why? a. Ne because the smaller atoms are packed more tightly together and harder to break apart. b. Ne because the LDFs between neon atoms are stronger, requiring more energy to overcome. c. F2 because the covalent bonds between fluorine atoms are stronger, requiring more energy to overcome d. F2 because the LDFs between fluorine molecules are stronger, requiring more energy to overcome. - ANSWER -F2 because the LDFs between fluorine molecules are stronger, requiring more energy to overcome.