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Chemistry Grade 9-12 Answer Key

Science: Naming Chemical Compounds

Practice naming ionic and covalent compounds

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Science: Naming Chemical Compounds

Practice naming ionic and covalent compounds

Chemistry - Grade 9-12

Instructions: Read each problem carefully. Write the correct chemical name or formula and show your reasoning when needed.
  1. 1

    Write the correct name for the ionic compound NaCl.

    Name the metal first, then the nonmetal with the ending changed to -ide.

    The correct name for NaCl is sodium chloride. Sodium forms a positive ion and chlorine forms the chloride ion.
  2. 2

    Write the correct chemical formula for calcium oxide.

    The correct formula for calcium oxide is CaO. Calcium forms a 2+ ion and oxide forms a 2- ion, so they combine in a 1:1 ratio.
  3. 3

    Write the correct name for FeCl3.

    Iron is a transition metal, so use a Roman numeral to show its charge.

    The correct name for FeCl3 is iron(III) chloride. Each chloride ion has a 1- charge, so three chloride ions require an iron ion with a 3+ charge.
  4. 4

    Write the correct chemical formula for aluminum sulfide.

    The correct formula for aluminum sulfide is Al2S3. Aluminum forms a 3+ ion and sulfide forms a 2- ion, so the charges balance with 2 aluminum ions and 3 sulfide ions.
  5. 5

    Write the correct name for CO2.

    For covalent compounds, use prefixes to show the number of atoms.

    The correct name for CO2 is carbon dioxide. The prefix di- shows that there are two oxygen atoms.
  6. 6

    Write the correct chemical formula for dinitrogen pentoxide.

    The correct formula for dinitrogen pentoxide is N2O5. The prefix di- means 2 nitrogen atoms and penta- means 5 oxygen atoms.
  7. 7

    Write the correct name for Cu2O.

    Find the charge on oxygen first, then determine the charge on copper.

    The correct name for Cu2O is copper(I) oxide. Oxide has a 2- charge, so each of the two copper ions must have a 1+ charge.
  8. 8

    Write the correct chemical formula for magnesium nitrate.

    The correct formula for magnesium nitrate is Mg(NO3)2. Magnesium forms a 2+ ion and nitrate is a 1- polyatomic ion, so two nitrate ions are needed.
  9. 9

    Write the correct name for N2O4.

    Watch for the vowel drop in the second prefix.

    The correct name for N2O4 is dinitrogen tetroxide. The prefix di- shows 2 nitrogen atoms, and tetra- becomes tetr- before oxide.
  10. 10

    Write the correct chemical formula for iron(III) hydroxide.

    The correct formula for iron(III) hydroxide is Fe(OH)3. Iron(III) is Fe3+ and hydroxide is OH1-, so three hydroxide ions are needed to balance the charge.
  11. 11

    Write the correct name for NH4Cl.

    This compound contains a common polyatomic cation.

    The correct name for NH4Cl is ammonium chloride. NH4+ is the ammonium ion and Cl- is the chloride ion.
  12. 12

    Write the correct chemical formula for sulfur hexafluoride.

    The correct formula for sulfur hexafluoride is SF6. The prefix hexa- shows that there are 6 fluorine atoms bonded to sulfur.
LivePhysics.com Chemistry - Grade 9-12 - Answer Key