Chem prelim

• What is the naming convention for a compound with two elements?

  Use both element names, second ends in -ide
• How do you name a compound with more than two elements including oxygen?

  Use names of other elements, second ends in -ate or -ite
• What is the chemical formula for water?

  H₂O
• What are diatomic molecules?

  Molecules made up of only two atoms
• Name two examples of diatomic molecules.

  HCl and CO
• How many diatomic elements are there?

  Seven
• What prefixes indicate the number of atoms in a compound?

  mono-, di-, tri-, tetra-, penta-, hexa-
• What is the chemical formula for carbon dioxide?


  CO₂
• What is the chemical formula for sulfur dioxide?

  SO₂
• What is the chemical formula for sulfur trioxide?

  SO₃
• What is the chemical formula for silicon tetrachloride?


  SiCl₄
• What is the chemical formula for phosphorous pentaiodide?

  PI₅
• What is the chemical formula for tungsten hexachloride?

  WCl₆
• How do you determine the chemical formula for compounds without prefixes?

  Use valency numbers of each element
• What is the valency of magnesium?

  2
• What is the valency of oxygen?

  2
• What are the steps to determine the chemical formula using valency?

  1. Write symbols of elements
  2. Write valency above symbols
  3. Cross the valencies
  4. Simplify if possible
  5. Write the formula
• What is a word equation?

  It shows reactants and products in a reaction
• What is produced when calcium carbonate reacts with hydrochloric acid?

  Calcium chloride, carbon dioxide, and water
• How does a word equation become a chemical equation?

  By replacing names with their formulae
• What must be true about the elements in a chemical equation?

  Same elements must appear on both sides
• What is the purpose of balancing a chemical equation?

  To ensure the same number of atoms on both sides
• What is the formula for calculating moles?

  n = m / GFM
• How many moles are in 30 g of calcium carbonate?

  0.3 moles
• How do you calculate the gram formula mass of calcium carbonate?

  1x 40 + 1x 12 + 3x 16 = 100g
• What is the mass of one mole of a gas if 0.25 moles has a mass of 7 g?

  28 g
• What is concentration expressed in terms of?

  Number of moles of solute per litre
• What is the unit for concentration?

  mol l⁻¹
• How do you calculate concentration?

  C = n / V
• What volume of 0.5 mol l⁻¹ solution contains 0.25 moles?

  0.25 l
• How do you convert cm³ to litres?

  Divide by 1000
• How do you calculate moles from concentration?

  n = C × V
• How many moles of sodium hydroxide are in 200 cm³ of a 0.4 mol l⁻¹ solution?

  0.08 moles
• What is the concentration of hydrochloric acid in a 50 cm³ sample containing 0.5 moles?

  10 mol l⁻¹
• What volume of a 2 mol l⁻¹ solution contains 0.5 moles of solute?

  0.25 l
• What is the relationship for calculating moles from balanced equations?

  Use the number of moles from the equation
• How do you calculate the mass of water produced from burning methane?

  Use the balanced equation and moles
• What is the general formula for alcohols?

  CH₂OH
• What is the functional group present in alcohols?

  Hydroxyl group (OH)
• What are the properties of alcohols?

  • Melting/boiling points increase with carbon chain length
  • Small alcohols burn easily with a clean flame
  • Solubility decreases with increasing size of molecule