Module 2: Foundation in Chemistry

Question 1

What is an isotope

Answer 1

An atom of the same element, with the same number of protons and electrons but different numbers of neutrons

Question 2

What are the three subatomic particles

Answer 2

Proton Neutron and Electron

Question 3

What are the charges of the subatomic particles

Answer 3

Proton+1
Neutron 0
Electron-1

Question 4

What is the mass of the subatomic particles

Answer 4

Proton 1
Neutron 1
Electron 1/1835

Question 5

State the equation of Relative atomic mass

Answer 5

=(mass1xabundance1)+(mass2xabundance2)/total abundance

Question 6

Why do Isotopes have the same physical properties but different chemical properties

Answer 6

1. They have the same number of electrons and protons
2. They have different masses

Question 7

Define Relative Isotopic mass

Answer 7

-The mass of an isoptope relative to 1/12th of the mass of a C-12 atom
-no units
-measured to 1d.p

Question 8

Define Relative Atomic mass

Answer 8

-The weighted mean mass of an atom of an element relative to 1/12th of the mass of a C-12 atom
-No unitss

Question 9

What does a spectrometer measure

Answer 9

The percentage abundance of each isotope in a sample of an element

Question 10

What happens in a spectrometer

Answer 10

1. A sample is placed in the mass spectrometer
   2.The sample is vapourised and ionised to form positive ions
2. The ions are accelerated
   4.The ions reach the detector and produce a signal. The greater the abudance of an isotope the greater the signal produced
   5.Mass spectrum data is given as % abundance vs. mass to charge ratio

Question 11

What are the 7 molecular ions

Answer 11

OH- hyrdoxide
NO3- Nitrate
NH4+ Ammonium
SO4-2 Sulfate
CO32+Carbonate
Zn2+ Zinc Ion
Ag+ Silver Ion

Question 12

How can we workout the formula of an ionic compound (give example)

Answer 12

Through the ‘‘swap and drop’ method
e.g
1. Ca2+ and NO3-
2. Ca-NO32+
Drop the charges
3.Ca and (NO3)2
4.Ca(NO3)2

Question 13

Water is a….

Answer 13

polar molecule it is attracted to ions in a salt. The &-O is attracted to positive ions and the &+H to negative ions

Question 14

What is water of crystallisation

Answer 14

A crystal structure in which water molecules can exist within

Question 15

What is the amount of substance

Answer 15

-n~ is the number of particles in a substance
-It is measured in moles, mol
-mol of a substance contains 6.02x10^23 particles.
-This number is known as the Avogadro constant Na

Question 16

what is molar mass and what is its unit

Answer 16

mass per mole
unit-g mol-1

Question 17

what is molar gas volume and what is its unit

Answer 17

gas volume per mole
unit-dm3 mol-1

Question 18

What si the equation for number of moles

Answer 18

amount of substance =mass (g)/ Mr or Ar (g mol-1)