Mole calculations - Higher

• What is the mole in chemistry?

  The mole is the unit for amount of substance.
• How can the number of particles in a substance be found?

  Using the Avogadro constant.
• What does the mass of a product depend on in a chemical reaction?

  It depends upon the mass of the limiting reactant.
• What is a balanced chemical equation?

  • A chemical equation using symbols and formulae
  • Shows the same number of units of each element on both sides of the arrow
• What is the definition of a mole?

  The amount of substance that contains the same number of particles as there are atoms in 12 g of carbon-12.
• What is the Avogadro constant?

  It is approximately \(6.0 \times 10^{23}\) number of particles.
• What are reactants in a chemical reaction?

  Substances present at the start of a chemical reaction.
• What are products in a chemical reaction?

  A substance formed in a chemical reaction.
• How can the masses of reactants and products be calculated?

  Using the amounts from balanced equations.
• In the equation \( \text{Zn}(s) + 2\text{HCl}(aq) \rightarrow \text{ZnCl}_2(aq) + \text{H}_2(g) \), how many moles of zinc react with hydrochloric acid?

  One mole of zinc reacts with two moles of hydrochloric acid.
• How many moles of oxygen react with 2 moles of magnesium in the equation \( 2\text{Mg}(s) + \text{O}_2(g) \rightarrow 2\text{MgO}(s) \)?

  1 mole of oxygen reacts with 2 moles of magnesium.
• What is the formula to calculate mass from a balanced equation?

  mass = relative formula mass × amount.
• If the relative formula mass of magnesium is 24, what is the mass of 2 moles of magnesium?

  48 g.
• How do you calculate the mass of sulfur dioxide produced from 16 g of sulfur in the reaction \( \text{S}(s) + \text{O}_2(g) \rightarrow \text{SO}_2(g) \)?

  32 g of sulfur dioxide is produced.
• In the reaction \( \text{N}_2(g) + \text{O}_2(g) \rightarrow 2\text{NO}(g) \), how much nitrogen is needed to produce 120 g of nitrogen monoxide (NO)?

  56 g of nitrogen is needed.
• How do you find the amount of nitrogen monoxide produced from 120 g of nitrogen?

  Calculate using the formula \( \text{Amount of NO} = \frac{\text{mass}}{\text{relative atomic mass}} \).
• What is the relative atomic mass of nitrogen (N) used in the calculations?

  14.
• What does the coefficient in a balanced equation represent?

  The amounts of the reactants and products.
• How does the mass of reactants relate to the mass of products in a chemical reaction?

  The mass of reactants equals the mass of products in a closed system.
• What are the steps to calculate the mass of a product from a given mass of reactant?

  1. Determine the amount of reactant using \( \text{amount} = \frac{\text{mass}}{\text{relative atomic mass}} \).
  2. Use the balanced equation to find the relationship between reactants and products.
  3. Calculate the mass of the product using \( \text{mass} = \text{relative formula mass} \times \text{amount} \).