Unit 1 ⚗️formulae and reaction quantities ⚗️

• What is the formula to calculate the number of moles?

  $n =$$\frac{m}{\text{GFM}}$
• How do you calculate mass from the number of moles?

  $m =$$n \times \text{GFM}$
• What does GFM stand for?

  Gram formula mass
• What is the formula for concentration?

  $C =$$\frac{n}{V}$
• What is the formula to calculate the number of moles from concentration and volume?

  $n =$$C \times V$
• What is the formula to calculate volume from moles and concentration?

  $V =$$\frac{n}{C}$
• What is the formula for percentage composition?

  <latex%\text{ by mass} = \frac{m}{\text{GFM}} \times 100</latex>
• What are the state symbols used in chemical equations?

  • Solid (s)
  • Liquid (l)
  • Gas (g)
  • Solution (aq)
• How do you name a compound that contains just two elements?

  The compound name consists of the names of both elements, with the second name ending in -ide.
• How do you name a compound with more than two elements that includes oxygen?

  The compound name consists of the names of the other elements, with the second name ending in -ate or -ite depending on the number of oxygen atoms.
• 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.

  Hydrogen chloride (HCl) and carbon monoxide (CO).
• What prefixes are used in naming compounds and their meanings?

  • mono-: one
  • di-: two
  • tri-: three
  • tetra-: four
  • penta-: five
  • hexa-: six
• What is the formula for carbon dioxide?

  CO₂
• What is the formula for sulfur trioxide?

  SO₃
• What is the formula for silicon tetrachloride?

  SiCl₄
• What is the formula for phosphorous pentaiodide?

  P I₅
• What is the formula for tungsten hexachloride?

  WCl₆
• What are group ions?

  Groups of atoms that carry a charge and stay together during chemical reactions.
• What is the formula for the sulfate ion?

  SO₄²⁻
• What is the valency of the sulfate ion?

  2
• What is the formula for the carbonate ion?

  CO₃²⁻
• What is the formula for the nitrate ion?

  NO₃⁻
• What is the formula for the hydroxide ion?

  OH⁻
• What is the formula for the ammonium ion?

  NH₄⁺
• What is the process for writing chemical equations?

  1. Write the word equation with reactants and products.
  2. Replace names with chemical formulae.
  3. Ensure the same elements appear on both sides.
• What is a balanced chemical equation?

  A chemical equation with the same number of atoms of each element on both sides.
• What is the mass of one mole of calcium?

  40 g
• What is the mass of one mole of calcium chloride?

  111 g
• How do you calculate the mass of calcium chloride produced from 8 g of calcium?

  Use the balanced equation and the mass ratio to find the mass produced.
• What is the formula for calculating the gram formula mass (GFM)?

  Add together all the relative atomic masses of each atom or ion in the chemical formula.
• How do you determine the GFM of sodium chloride (NaCl)?

  Add the atomic masses of sodium (Na) and chlorine (Cl).
• How do you calculate the GFM of magnesium nitrate, Mg(NO₃)₂?

  Add the atomic masses of magnesium, nitrogen, and oxygen, considering the brackets.
• What is the relationship between moles and grams?

  1 mole of a substance has a mass equal to its GFM in grams.
• How do you calculate the mass of 2 moles of sodium chloride (NaCl)?

  Use the formula $m =$$n \times \text{GFM}$ with $n =$$2$ and $\text{GFM} =$$58.5 \text{ g}$.
• How do you calculate the number of moles in 10 g of calcium carbonate (CaCO₃)?

  Use the formula $n =$$\frac{m}{\text{GFM}}$ with $m =$$10 \text{ g}$ and $\text{GFM} =$$100 \text{ g}$.
• How do you calculate the mass of one mole of a gas if 0.25 moles has a mass of 7 g?

  Use the relationship $\text{GFM} =$$\frac{m}{n}$ to find $\text{GFM} =$$\frac{7 \text{ g}}{0.25} =$$28 \text{ g}$.
• What is the concentration of a solution expressed in?

  In terms of the number of moles of the solute in one litre of solution.
• How do you calculate the number of moles of sodium hydroxide in 200 cm³ of a 0.4 mol⁻¹ solution?

  Convert 200 cm³ to litres and use $n =$$C \times V$.