Atoms, Ions and Compounds

Question 1

what is an isotope?

Answer 1

atoms of the same element with the same number of protons and different number of neutrons

Question 2

what is relative isotopic mass?

Answer 2

the mass of an atom of an isotope compared with one twelfth of the mass of an atom of carbon-12.

Question 3

what is relative atomic mass?

Answer 3

the weighted mean mass of an atom of an element compared to one twelfth of an atom of carbon-12

Question 4

what does the contribution made by an isotope to the overall mass depend on?

Answer 4

1) the % abundance of each isotope
2) the mass of the isotope

Question 5

qualitative analysis ion tests and observations

Answer 5

1) CO32- -add nitric acid- effervescence
2) SO42- -add barium chloride/ barium nitrate- white precipitate
3) Cl- - add silver nitrate- white precipitate
4) NH4+ - warm with sodium hydroxide and test gas evolved with damp red litmus paper- litmus paper turns blue

Question 6

why are the qualitative ion tests done in the order they are?

Answer 6

1)CO32- -only 1 positive result, so no false positives
2)SO42- -have to do carbonate before, so you can’t get barium carbonate (also a white precipitate)
3) Cl*- - have to remove silver sulfate and silver carbonate as false positives- they’re all white precipitates

Question 7

draw a diagram of a mass spectrometer

Answer 7

Question 8

what do the m and z on the x-axis of a mass spectrometer mean?

Answer 8

m= relative mass
z= charge

Question 9

list these ions:
ammonium
hydroxide
nitrate
carbonate
sulfate
phosphate
silver
zinc

Answer 9

NH4+
OH-
NO3-
CO3 2-
SO4 2-
PO4 3-
Ag+
Zn 2+