Paper 1 - Quantitative chemistry

Question 1

*Actual yield:

Answer 1

The amount of product actually produced by a reaction.

Question 2

*Atom economy:

Answer 2

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

Question 3

Concentration

Answer 3

: The amount of substance (e.g. the mass) in a certain volume of a solution.

Question 4

Avogadro constant:

Answer 4

: The number of atoms, molecules or ions in a mole of a given
substance.

Question 5

*Avogadro’s law

Answer 5

Equal amounts in moles of gases occupy the same volume under the
same conditions of temperature and pressure.

Question 6

Conservation of mass:

Answer 6

: The law of conservation of mass states that no atoms are lost or
made during a chemical reaction so the mass of the products equals the mass of the
reactants.

Question 7

Limiting reactant:

Answer 7

: The reactant that is completely used up since it limits the amount of
products formed.

Question 8

*Mole

Answer 8

Chemical amounts are measured in moles. The mole is the unit for amount of
substance. The symbol for the unit mole is mol.

Question 9

*Percentage by mass

Answer 9

A value representing the concentration of an element in a compound
or a component in a mixture. It is calculated by the mass of a component divided by the total
mass of the mixture, multiplied by 100.

Question 10

*Percentage yield

Answer 10

The percentage ratio of the actual yield of product from a reaction
compared with the theoretical yield.

Question 11

Relative formula mass

Answer 11

: The sum of the relative atomic masses of the atoms in the numbers
shown in the formula. It is numerically equal to the mass of one mole of a substance in
grams

Question 12

*Theoretical yield:

Answer 12

: The maximum amount of product that could be produced from the given
reactants, assuming a complete reaction takes place.

Question 13

Thermal decomposition:

Answer 13

: The reaction that occurs when heat is applied to a compound
causing it to break down into its different chemical constituents.

Question 14

Uncertainty

Answer 14

All measurements have a degree of uncertainty regardless of precision and
accuracy. Uncertainty can be due to the limitations of the measuring equipment or due to the
skill of the experimenter carrying out the measurements

Question 15

what is the law of conservation of mass?

Answer 15

the law of conservation of mass states that no atoms are lost or made during a chemical reaction so the mass of products equals the mass of the reactants

Question 16

define relative atomic mass and relative formula mass

Answer 16

ram - average mass of atoms in an element taking into account masses and abundance of its isotopes
rfm- sun of rams of all atoms in the formula

Question 17

what is titration?

Answer 17

a technique for finding the concentration of a solution by reacting a known volume of this solution with a solution of known concentration

Question 18

what is atom ecenomy?

Answer 18

a measure of the amount of starting materials that end up as useful products . Its is a ratio of the relative formula of desired product to the sum of relative formula masses of reactants