Quantitative Chemistry for Separate Science

What does the law of conservation of mass state?

That no atoms are lost or made during a chemical reaction

What is the relative formula mass of a compound?

The sum of the relative atomic masses of the atoms in the compound

Some reactions can appear to involve a change in mass. What is a common explanation for this?

A product is a gas whose mass has not been taken into account

What are chemical amounts measured in?

Moles

What is the symbol for the unit mole?

Mol

One mole of a substance contains how many atoms?

6.02 x10^23 atoms

What is Avogadro's Constant?

6.02 x10^23 atoms

What do we call the reactant that is completely used up in a reaction?

The limiting reactant

What is the unit for measuring the concentration of a solution?

g/dm3

What is the equation to work out the concentration of a solution?

Concentration \= Mass/Volume

Why is not always possible to obtain the calculated amount of a product?

the reaction may not go to completion because it is reversible
some of the product may be lost when it is separated from the reaction mixture some of the reactants may react in ways different to the expected reaction

What is the amount of a product obtained as known?

Yield

What do we call the compression of the maximum theoretical amount to obtained amount?

Percentage Yield

What is the equation to calculate percentage yield?

What is atom economy (atom utilisation)?

A measure of the amount of starting materials that end up as useful products

What is atom economy important for?

Sustainable development
Economic reasons

What is the equation to calculate the percentage atom economy of a reaction?

What does a reaction pathway describe?

The sequence of reactions needed to produce a desired product

What factiors will be involved in deciding on the pathway for a chosen product?

Percentage yield
Atom economy
Rate of reaction
Equilibrium position
Usefulness of by-products

What can the concentration of a solution be measured in?

mol/dm3

What can be calculated from a solution's concentration?

Amount of moles of solute
Mass in grams of solute in a given
volume of solution

What do you need to know to be able to calculate the concentration of an unknown solution?

The volumes of the two solutions
Concentration of one of the solutions

What is the concentration of a solution in mol/dm3 related to?

The mass of the solute
The volume of the solution

What do equal amounts in moles of gases do when they occupy the same volume?

Temperature
Pressure

What is the volume of one mole of any gas at room temperature (20oC and 1 atmosphere pressure)?

24dm3

What can be calculated from the balanced equation of a reaction?

The volumes of gaseous reactants and products

What do you need to calculate the volume of gas at room temperature and pressure?

Mass
Relative Formula Mass