chemistry - 3c - stoichiometric calculations

Question 1

What is stoichiometry?

Answer 1

The study of mole relationships involved in chemical reactions.

Question 2

What can chemical equations, using formulae and state symbol, be written and balanced to show?

Answer 2

The mole ratio(s) of reactants and products, including multi-step reactions.

Question 3

What is the mass of a mole of any substance, in grams (g), equal to?

Answer 3

The gram formula mass (GFM) and can be calculated using relative atomic masses.

Question 4

For solutions, what can be calculated from data provided?

Answer 4

For solutions, the mass of solute (grams or g), the number of moles of solute (moles or mol), the volume of solution (litres or l), or the concentration of the solution (moles per litre or mol l-1).

Question 5

What is percentage by mass?

Answer 5

The mass of solute made up to 100 cm3 of solution.

Question 6

What is percentage by volume?

Answer 6

The number of cm3 of solute made up to 100cm3 of solution.

Question 7

What does the unit ppm stand for?

Answer 7

Parts per million and refers to 1 mg per kg or 1 mg per litre.

Question 8

How is the percentage yield reduced?

Answer 8

By…
- mass transfer or mechanical losses
- purification of product
- side reactions
- equilibrium position