Chemistry Final Questions And Answers – Flashcards
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The mass of a molecule is found by
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adding the masses of all the atoms in a the molecule
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For any molecule, formula unit, or ion, the sum of the adverse atomic masses of all the atoms represented in a formula are
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formula mass
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What is the correct formula for zinc hydroxide, Zn(OH)2
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99.41 amu
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One mole of potassium atoms has a mass of
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39.10 g
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A compounds molar mass is numerically equal to
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its formula mass
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How many total moles of atoms are there in one mole of silver (I) phosphate, Ag3PO4
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8
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Which statement shows how to correctly convert from the mass of a compound in grams to the amount of that compound in moles.
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molar mass X 1/mass = amount (moles)
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The percentage composition of a compound
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the percentage by mass of each element in the compound
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What is the percentage of iron in iron (III) chloride, FeCl3? The molar mass of FeCl3 is 162.2 g/mol
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34.43%
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The smallest whole number ratio of atoms of each element, com pined in the simplest unit of a chemical compound is known as
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empirical formula
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What is the empirical formula for benzene, C6H6
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C3H3
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What other information do you need in order to determine the molecular formula from the empirical formula of a compound
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the number of moles in a compound
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What is the empirical formula for a compound that contains 1.18 mol Na, 1.18 mol N, and 3.53 mol O
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NaNo3
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What is the empirical formula for a compound that contains 83.01% K and 16.98% O by mass
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k5O
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What is the empirical formula for C3H6O3
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...
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NaCl is
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both an empirical formula and a chemical formula
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what is the molecular formula for the compound with an empirical formula for NO2, and a formula mass of 92.02 amu
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N2O4
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Formula for copper(II) carbonate
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CuCO3
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Formula for tin (IV) Sulfide
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SnS2
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name for Mg(ClO4)2
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magnesium perchlorate
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name for Fe(NO2)3
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iron (III) nitrate
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formula for sodium hydroxide
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NaOH
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Ionic bonds form as a result of electrostatic attraction between
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ions
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The measure of an atoms ability to attract electrons is its
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electronegativity
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Atoms that are bonded with an electronegativity difference of 0 to 0.3 are generally considered to be
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nonpolar- covalent compounds
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0.4-1.9
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polar covalent
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2.0-3.3
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ionic
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what is the apparent charge on the chlorine ago in the molecule HCI
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-1
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Atoms seldom exist as independent particles in nature because
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atoms are more stable when they combine with other atoms
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When an atom completely gives up its valence electrons to another atom, they form a bond that is considered to be
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purely ionic
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You can estimate the degree to which a bond between two atoms is ionic or covalent by calculating the
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difference in the atoms electronegative
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The chemical bond between atoms results from the attraction between the valence electrons and
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nuclei
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A Covalent bond consists of
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a shared electron pair
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If two covalently bonded atoms are identical the bond is identified as
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non polar covalent
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Atoms with a strong attraction for electrons they share with another atoms exhibit
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high electronegativity
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An electron that is in the highest energy level of an atom and determines the atoms chemical properties
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valance electrons
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The atomic radius of an atom that is chemically bonded to an identical atom is equal to
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half the distance between the nuclei
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Across a periodic table, atoms radii
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decreases
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down a periodic table atomic radii
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increases
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One of the least electronegative elements would be found on the periodic table in
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Group 1, Period 7
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An element with the smallest anionic radius would be found on the periodic table in
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Group 17, Period 2
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If two covalently bonded atoms move close than a distance of the bond length, the potential energy of the atoms
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increase
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Bond length between two bonded atoms is
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the separation at which their potential energy is minimum
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In a double covalent bond
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one atom loses a pair of electrons
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An ionic compound is not represented by a molecular formula because an ionic compound
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lacks molecules
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compared with the energies of neutral atoms that form the ions, a crystal lattice has
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lower potential energy
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The salts NaCl(s) and CaCl2(s)
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are held together by ionic bonds
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Compared with solid ionic compounds, solid molecular compounds generally
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have lower melting points
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Because strong attractive forces hold the layers in an ionic crystal in relatively fixed positions, ionic compounds
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are hard, brittle, and not electrical conductors as solids
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In a crystal of sodium chloride, how many oppositely- charged ions does each Na and Cl ions have clustered around it
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6
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The arrangement of ions in a crystal structure and the strengths of the attractions between them vary with the
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sizes of the ions, charges of ions, numbers of ions of dif. charges.
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The energy released when one mole of an ionic crystalline solid is formed from ions in the gas state is known as
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lattice energy
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Some ionic compounds do not dissolve in water because
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the attractions between the water molecules and the ions are not as strong as the attractions between the ions
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A charged group of covalently bonded atoms is known as
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polyatomic
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Chemical bonding in metals is
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different from ionic or covalent bonding
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The Valance electrons in a metallic bond
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move freely throughout the network of metal atoms
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Within a metal, the vacant orbitals in the atoms' outer energy levels
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overlap
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Result of Visible light absorbed by metal
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light at a frequency similar to the absorbed frequency is emitted
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Metals are malleable because when struck, one plane of metal atoms
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can slide past another plane without breaking bonds
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Measure of Metallic bond strength
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enthalpy of vaporization
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What is responsible for the good electrical conductivity of metals
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the ability of electrons to move freely about the crystal structure
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the arrangement of valence electrons in a metallic bond is best described as
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a sea of free-moving electrons
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An element that has the electron configuration of [Ne] 3s2 3p5 is in period
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3
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An element that is [Ne] 3s2 3p5 is in group
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7
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Elements in group 18 have
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very low reactivity
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Nonmetallic elements in group 17 that react with most metals form
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Halogens
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An element found in groups 3-12 of the periodic table are classified as
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transition metals
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statement that no two electrons in the same atom can have the same four quantum numbers is a restatement of
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Hunds rule
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Separating unpaired electrons into as many orbitals as possible
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minimizes the repulsion between electrons
