2.1.1-Atomic structure and isotopes

Question 1

relative isotopic mass

Answer 1

mass of an isotope compared to 1/12th of mass of an atom of carbon-12

Question 2

relative atomic mass-Ar

Answer 2

weighted mean mass of an atom of an isotope compared to 1/12th of mass of an atom of carbon-12

Question 3

what does the weighted mean mass take into account

Answer 3

-mass of each isotope
-percentage abundance of each isotope
-so number in periodic table

Question 4

relative molecular mass use

Answer 4

in covalent molecules

Question 5

relative formula mass

Answer 5

for ionic compounds and other giant structures

Question 6

how to calculate relative molecular or formula masses

Answer 6

adding all the Mr’s

Question 7

isotopes

Answer 7

atoms of the same element with the same number of electrons and protons but different number of neutrons and different masses

Question 8

describe why isotopes have similar chemical properties

Answer 8

-have same number of electrons in their shells
-as an atom of that element and their arrangement is same

Question 9

what is the standard element that all elements are compared to

Answer 9

carbon-12

Question 10

use of mass spectrometer

Answer 10

to determine the relative isotopic masses and relative abundances of isotopes

Question 11

relative molecular mass-Mr

Answer 11

the mean mass of a molecule compared to 1/12th of mass of an atom of carbon-12

Question 12

Atom economy for each reaction type

Answer 12

addition reaction -100 percent
substitution -less
elimination-less

Question 13

decomposition reaction

Answer 13

one reactant broken apart into multiple reactions

Question 14

detector in mass spectrometry

Answer 14

-electric or photographic detection methods

Question 14

how are percentage abundances in isotopes found w mass spectrometer

Answer 14

1-sample placed in mass spec,vapourised to form +ve ions
2-ions accelerated-heavier move more slowly and difficult to detect so ions of different isotopes separated
3-ions detected as a mass to charge ratio-m/z
greater the abundance he greater the signal

Question 15

How to calculate number of protons neutrons and electrons for neutral atoms and ions?

Answer 15

neutral atoms
number of elec=number of protons
number of neutrons =mass number - atomic number

ions
number of electrons less than number of protons-+
number of electrons more than number of protons- -
charges affect ions

Question 16

how to get moles of unkown chemical

Answer 16

mole ratio

Question 16

how to work out relative formula or molecular mass?

Answer 16

add up all the mass numbers

Question 17

limiting reagent vs excess reagent

Answer 17

limiting reagent
-limits maximum/theoretical amount of product that can form
-is the reacttant totally used up in a reaction

excess reagent
-has some left over after reaction

Question 17

mass number and atomic number

Answer 17

mass number = number of protons and neutrons

atomic number= number of protons

Question 18

solute and solvent

Answer 18

solute-substance being dissolved
solvent-dissolved in most commonly H2O

Question 18

state equation for hydrated salt CuSO4 .5 H2O being heated

Answer 18

CuSO4 .5 H2O ———- CuSO4 + 5H2O

-when hydrated salts are heated,the water driven off and compound left is referred to as the anhydrous salt

Question 19

state why group 0 do not form ions

Answer 19

-noble gases are non metals
-already have full outer energy level which other atoms strive to have.

Question 19

what does mass spectrometer consist of

Answer 19

ion source
analyser
detector

Question 20

what does the mass number and atomic number determine

Answer 20

mass number-physical properties
protons and neutrons
atomic number-chemical properties
protons

Question 20

what happens to chemical activity in isotopes?

Answer 20

-does not change
-chemical activity determined by atomic number which is number of protons that does not change
-as isotopes have same number of protons and electrons

Question 21

what solutions dont have an impact on dry litmus paper

Answer 21

when no aqueous hydrogen ions present
if present of H+ ion turns red