Topic 3- Quantative Chemistry

Question 1

Conservation of mass

Answer 1

No atoms are lost or gained in a reaction
Mass stays the same In a closed system

Question 2

Relative formula mass (Mr)

Answer 2

Sum of the relative atomic masses of the atoms in the numbers shown in the formula
In a balanced equation sum of the mr of reactants is equal to the products

Question 3

Moles

Answer 3

Mol
1mol= mass in grams numerically equal to relative formula mass
1mol always contains 6.02*10^23 atoms

Question 4

Limiting reactant

Answer 4

Reactant that is completely used up in the equation
Limits the amount of product

Question 5

Yield

Answer 5

Not always possible to obtain the calculated product
Reaction may not go to completion
Product may be lost when separated from reaction mixture

Question 6

Percentage yield

Answer 6

Mass of product made / maximum theoretical product × 100

Question 7

Atom economy

Answer 7

Measure of the amount of starting materials that end up as useful products
Important for sustainable development

Question 8

Percentage atom economy

Answer 8

Relative formula mass of desire product / sum of relative formula masses of all reactants × 100

Question 9

Concentration

Answer 9

Mol/dm^3

Question 10

Moles of gas at room temp

Answer 10

Equal moles of gases occupy same volume under the same conditions
20°C and 1 atmosphere pressure = gas is 24dm^3