amount

Question 1

Ar (4)

Answer 1

• relative atomic mass
• the average mass of one atom of an element, relative to carbon-12 which has a mass of exactly 12)
• Ar = (average mass) / (1/12)(mass of one C-12 atom)
• measured in amu

Question 2

Mr (2)

Answer 2

• relative molecular mass

- average mass of a molecule relative to c-12

Question 3

mole (4)

Answer 3

• molar mass
• 6.02( 10^23) (Avogadro’s number)
• the amount of any substance that contains the same number of elementary particle as 12g)
• measured in g/mol

Question 4

standard solution (1)

Answer 4

• a solution of which the concentration is known exactly and is unlikely to change for a period of time

Question 5

empirical formula (1)

Answer 5

• the formula that shows the simplest ration of elements in a compound

Question 6

molecular formula (1)

Answer 6

• the formula that shows the actual ration of elements in a compound

Question 7

law of conversion of matter (1)

Answer 7

• matter can not be created or destroyed, only transferred from one place to another

Question 8

formula (10)

Answer 8

• n = number of moles
• m = mass
• Mr = relative molecular mass
• v = volume
• Vm = volume of a mole
• c = concentration
• n = m/Mr
• n = v/Vr
• c = n/v
• n = c (n)

Question 9

gasses (2)

Answer 9

• STP (standard Temperature and Pressure)

- Vm = 22.4 dm^3

Question 10

solutions (4)

Answer 10

• solute (dissolvable substance)
• solvent (dissolving substance)
• solution (product of a solute and solvent combining)
• standard solution ( the concentration is known exactly and is unlikely to change for a period of time)

Question 11

percentage composition (1)

Answer 11

• PC = (mass of atom) / mass of mole

Question 12

empirical formula (1)

Answer 12

• Ef = molar ration

Question 13

balancing equations (2)

Answer 13

• if an equation is to obey the law of conservation, then the no. or moles of particles must remain the same at the beginning and the end
• coefficients at the beginning of each atom must equal