chemistry exam 4 – Flashcards

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question
What is the molecular geometry of NH3?
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triagonal pyramidal
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molecular geometry of CO2
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linear
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molecular geometry of H2O
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bent
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what is value of bond angles in SICL4
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109.5 degrees
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what is value of bond angles in BCl3
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120 degrees
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what is value of bond angle in I3
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180 degrees
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what shape would you expect for XeF4
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square planar
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what are the expected bond angles in ICl4
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90,120,180
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linear
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2 outer atoms 0 lone pairs 2 charge clouds
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trigonal planar
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3 outer atoms, 0 lone pairs, 3 charge clouds
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bent
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2 outer atoms 0 lone pairs 3 charge clouds
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tetrahedral
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4 outer atoms 0 lone pairs 4 charge clouds
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trigonal pyramidal
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3 outer atoms 1 lone pair 4 charge clouds
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bent also
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2 outer atoms, 2 lone pairs, 4 charge clouds
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trigonal bipyramidal
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5 outer atoms, 0 lone pairs 5 charge clouds
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seesaw
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4 outer atoms 1 lone pair 5 charge clouds
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T-shaped
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3 outer atoms 2 lone pairs 5 charge clouds
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linear also
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2 outer atoms 3 lone pairs 5 charge clouds
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octahedral
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6 outer atoms 0 lone pairs 6 charge clouds
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square pyramidal
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5 outer atoms 2 lone pairs 6 charge clouds
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square planar
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4 outer atoms 2 lone pairs 6 charge clouds
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sp
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linear
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sp2
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trigonal planar
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sp3
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tetrahedral
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sp3d
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trigonal bipyramidal
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sp3d2
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octahedral
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What is the electron-domain (charge-cloud) geometry of BrF5?
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octahedral
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What is the molecular geometry of BrF5?
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square pyramidal
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Ignoring lone pair effects, what is the smallest bond angle in BrF5?
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90 degrees
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What is the hybridization about the central atom in BrF5?
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sp3d2
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Which choice best describes the polarity of BrF5?
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polar bonds/polar molecule
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How many valence electrons are in an atom of chlorine?
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valence = 7 electrons
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In the molecule ClF5, chlorine makes five covalent bonds. Therefore, five of its seven valence electrons need to be unpaired. How many degenerate orbitals are needed to contain seven electrons with five of them unpaired?
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number of orbitals=6
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What is the name of the hybrid orbitals used by chlorine in ClF5?
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sp3d2
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What the molecular shape (geometry) of CHClO?
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trigonal planar
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What are the approximate bond angles in CHClO?
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120 degrees
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What type of hybridization is exhibited by the central atom in CHClO?
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sp2
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Molecular orbitals
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stability, bond length, bond order, and magnetism of a molecule can be predicted from its molecular orbital configuration
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rank F2+ F2 and F2- most stable to least
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F2+ F2 F2-
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ideal gas law
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PV=nRT pressure, volume liters, n moles, 8.3 gas constant, T in kelvin
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mole fraction
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X= moles of component 1/total moles in mixture
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partial pressure
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mole fraction x total pressure
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partial pressure and ideal gas law
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P total= (n1+n2+n3+..)RT/ V = nTotal RT/V
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sample of gas containing molecules of different masses are true
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more-massive gas molecules in the sample have lower rms speed than less-massive ones
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Density:
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In both solids and liquids, the molecules are held very closely together and therefore their densities are about the same. In gases, there is space between the molecules.
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Molecular movement and order
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The molecules in solids are arranged in a regular pattern that does not allow for diffusion, although does allow for vibrations. The arrangement of molecules in a liquid, although not completely random, is not completely fixed. Molecules in a gas are randomly arranged and move very quickly. Gases diffuse quickly in comparison to liquids.
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Compressibility and thermal expansion:
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Since the molecules in solids and liquids are already very close together, applying pressure does not greatly affect the volume. In contrast, the space between gas molecules allows for a great deal of compressibility. Although temperature changes will cause slight variations in the volume of a solid or liquid, those variations are negligible compared to the thermal expansion of a gas.
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Shape and expansion:
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A solid does not take the shape of its container, nor does it expand to fill the container. A liquid takes the shape of its container but does not expand to fill it. A gas takes the shape of its container and expands to fill it.
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Consider equal volumes (say 1 L) of a given substance in the solid, liquid, and gas phases. Arrange them in order of decreasing mass based on the trend for the average substance. If the mass difference between samples is relatively small (10% or less), rank the items as equivalent.
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1 L of substance in the solid phase 1 L of substance in liquid phase (same) 1 L of substance in the gas phase
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strong intermolecular forces
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high viscosity high boiling point high surface tension low vapor pressure
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weak intermolecular forces
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low surface tension low boiling point low viscosity high vapor pressure
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intermolecular forces
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describe the attractions between two or more molecules.
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Dipole-dipole
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result from the attraction of the positive end of one polar molecule to the negative end of another polar molecule.
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Hydrogen bonding
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a particularly strong type of dipole-dipole force that occurs when hydrogen is attached to nitrogen, oxygen, or fluorine. Water is an example of a substance in which hydrogen bonding occurs. Because of oxygen's high electronegativity and the electron deficiency of the hydrogen atom, the hydrogen atoms are attracted to the lone pairs of electrons on the oxygen of another water molecule.
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dispersion forces, also known as London forces
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These forces are very weak and are only important in the absence of any other intermolecular force. Nonpolar covalent molecules and single-atom molecules are examples of substances that lack all other intermolecular forces except for dispersion. Dispersion forces result from shifting electron clouds, which can cause a weak, temporary dipole.
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example of dipole-dipole forces
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NF3
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example of hydrogen bonding
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NH3
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example of dispersion forces
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CH4
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classify diamond
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covalent
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classify sodium sulfide
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ionic
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classify pure sodium
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metallic
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classify frozen carbon dioxide
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molecular
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rank diamond, potassium chloride and ice highest to lowest melting point
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diamond, potassium chloride and ice
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Which of the following would you expect to be characteristic of a solid with the formula P4?
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poor thermal conductivity low melting point
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An unknown substance has a melting point of 1455 ?C, is insoluble in water, conducts electricity as a solid, and is hard. Given these properties, which of the following are possible identities for the unknown substance?
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Ni
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An unknown substance has a melting point of 1000 ?C, is soluble in water, does not conduct heat as a solid, and is hard. Given these properties which of the following are possible identities for the unknown substance?
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NiCl2
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Polonium is a radioactive metal that is used as a heat source in space satellites. Polonium has a simple cubic unit cell. How many atoms of Po are present in each unit cell?
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1
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Silver has a face-centered cubic unit cell. How many atoms of Ag are present in each unit cell?
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4
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Chromium has a body-centered cubic unit cell. How many atoms of Cr are present in each unit cell?
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2
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sublimation critical point melting freezing triple point boiling deposition condensation
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E to F B E to C C to E A C to D F to E D to C
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At 100?C and 1 atm, water is in which phase?
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liquid-gas equilibrium
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At ?78?C and 5.2 atm, carbon dioxide is in which phase?
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solid
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At 0?C and 1 atm, carbon dioxide is in the gas phase. From these conditions, how could the gaseous CO2 be converted into liquid CO2?
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increase the pressure
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forming solute-solvent attractions
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exothermic
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breaking solute-solute attractions breaking solvent-solvent attractions
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endothermic
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The enthalpy of solution for a solid with ?H values of approximately equal magnitude for each of the steps involved in the solution formation process is __________.
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slightly endothermic
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solubility=
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k * P k is characteristic of the specific gas (mols/L) P is the partial pressure of the gas over the solution usually expressed in atmospheres
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mass % =
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mass of component
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