Quantitative chemistry

• In which fields do nanoparticles have applications?

  Medicine, electronics, cosmetics, and catalysts
• What possible risks are associated with nanoparticles?

  There are possible risks in their use
• What do chemists use quantitative analysis for?

  To determine formulae and reaction equations
• Why is identifying different types of chemical reactions important?

  It helps establish patterns and make predictions
• What does the law of conservation of mass state?

  No atoms are lost or made in reactions
• How are chemical reactions represented?

  By balanced symbol equations
• What is the relative formula mass (Mr) of a compound?

  Sum of relative atomic masses in the formula
• What does a balanced chemical equation represent?

  Equal sum of relative formula masses of reactants and products
• How can mass changes in reactions be explained?

  By considering gases not accounted for
• What is always present in measurements?

  Some uncertainty about the result
• What unit is used to measure chemical amounts?

  Moles (mol)
• What is the mass of one mole of a substance in grams?

  Numerically equal to its relative formula mass
• What does one mole of a substance contain?

  The same number of particles as any other mole
• What is the value of the Avogadro constant?

  $6.02 \times 10^{23}$ per mole
• How can the relative formula mass be used?

  To calculate the number of moles in a given mass
• How can masses of reactants and products be calculated?

  From balanced symbol equations
• What does the equation $Mg +$$2HCl \rightarrow MgCl_2 +$$H_2$ represent?


  One mole of magnesium reacts with two moles of hydrochloric acid
• What should students be able to calculate from a balanced symbol equation?

  The masses of substances shown
• How can balancing numbers in equations be calculated?

  By converting masses to amounts in moles
• What is a limiting reactant?

  The reactant that is completely used up
• How does a limiting reactant affect product amounts?

  It limits the amount of products obtainable
• How can the concentration of a solution be measured?

  In mass per given volume, eg g/dm³
• What is the percentage yield of a product?

  Comparison of actual yield to maximum theoretical yield
• How is percentage yield calculated?

  % Yield = $\frac{Mass \ of \ product \ actually \ made}{Maximum \ theoretical \ mass \ of \ product} \times 100$
• What is atom economy?

  A measure of starting materials as useful products
• How is percentage atom economy calculated?

  % Atom Economy = $\frac{Relative \ formula \ mass \ of \ desired \ product}{Sum \ of \ relative \ formula \ masses \ of \ all \ reactants} \times 100$
• How can the concentration of a solution be measured in chemistry?

  In mol/dm³
• How can the amount in moles of solute be calculated?

  From its concentration in mol/dm³
• How can the concentration of a solution relate to mass and volume?

  Concentration=Mass of Solute in Solution / (g)Volume of Solvent 
• What is Yield?


  The amount of Products of a reaction.
• What is Theoretical Yield?

  Theoretical Yield is the predicted amount of yield based on calculations.
• What are the Reasons why we may Not Make as Much Products in a Reaction?

  1.Reactants might not all react (Reversible or slow reactions)

  2.Side Reactions - Reactants may react with a different product which usually happens with oxygen.

  3.Loss of Products i.e Gases Escaping