CHAPTERS 7.1-7.4

Question 1

what is relative mass?

Answer 1

mass used in chemistry, it is based on a comparison to carbon-12

Question 2

what is the relative atomic mass (Ar)?

Answer 2

the weighted average of all the relative isotopic masses for the isotopes that make up the naturally occurring isotopic mixture of an element (the mass in the periodic table)

Question 3

what is the relative isotopic mass?

Answer 3

the mass of an individual isotope of an element

Question 4

what is the relative isotopic abundance?

Answer 4

the percentage abundance of an isotope in the natural environment

Question 5

what is avogadro’s constant (NA)?

Answer 5

6.02 x 10 (to the power of 23)

Question 6

what is 1 mol equal to?

Answer 6

6.02 x 10 (to the power of 23) particles

Question 7

what is the empirical formula of an ionic compound?

Answer 7

it indicates the number of each ion in one formula unit of the compound

Question 8

what does each n mean in n = N/NA

Answer 8

n = number of moles, unit mol
N = the actual number of particles
NA = avogadro’s constant (6.02 x 10 (to the power of 23))

Question 9

what does each part of n = m/M stand for?

Answer 9

n = number of mol
m = mass (g)
M = molar mass (g mol-1) on the period table

Question 10

how is the percentage composition by mass determined?

Answer 10

from the chemical formula of the compound using the molar mass of the element and the molar mass of the compound