foundations in chemistry

Question 1

atomic number the big or small number

Answer 1

small

Question 2

Relative isotopic mass

Answer 2

The mass of an atom of an element compared to 1/12th of the mass of carbon 12

Question 3

Relative atomic mass

Answer 3

The average mass of an atom of an element compared to 1/12th of the mass of carbon 12

Question 4

how does mass spectrum work

Answer 4

samples is vapourised
sample is ionised to form positive ions
ions are accelerated and heavy ions move slower
ions are detected as a mass to charge ration m/z
each ion produces a signal large signal=greater abundance

Question 5

Spectrometer- why a vacuum

Answer 5

stop ions from colliding with particles in air

Question 6

Uses of mass spectrometry

Answer 6

.In radioactive dating(carbon 14 is radioactive. It can be measured to date archaeological finds)
.To detect steroid use in sport
.In the pharmaceutical industry(new pharmaceuticals can be found using mass spec and to test the purity of pharmaceuticals in the manufacturing industry)

Question 6

Suggest why the second ionisation energy of oxygen has a greater value than the first ionisation energy of oxygen.

Answer 6

the O+ ion, is smaller than the O atom
OR
the electron repulsion/shielding is smaller
OR
the proton : electron ratio in the 2+ ion is greater than in the 1+ ion

Question 7

Define the term first ionisation energy.

Answer 7

the energy required to remove one electron from each atom in one mole of gaseous atoms forming a uni positive ion

Question 8

relative mass of an electron

Answer 8

1/1836

Question 9

relative mass of proton and neutron

Answer 9

1

Question 10

orbital

Answer 10

region around the nucleus that can hold up to 2 electrons with opposite spins

Question 11

number of particles in a mol

Answer 11

Avogadro’s constant

Question 12

mol particles and av

Answer 12

n=partciles/av

Question 13

electrons are arranged around nucleus in

Answer 13

principal energy levels

Question 14

polyatomic ions

Answer 14

ions with more than one type of element

Question 15

phosphate ion

Answer 15

PO4 3-

Question 16

zinc ions

Answer 16

Zn 2+

Question 17

carbonate ions

Answer 17

CO3 2-

Question 18

relative formula mass vs molecular mass

Answer 18

molecular is for fixed formulas
formula mass is for ionic or giant covalent compounds, chemicals that use empirical formulas

Question 19

PV=NRT units

Answer 19

Pa M^3 mol Jmol-1K-1 k

Question 20

kinetic theory of gas

Answer 20

gaseous molecules move fast and randomly
molecules have hardly any volume
gaseous moles do not attract/repel each other
no ke is lost when mols collide with each other
temp of gas relative to ke

Question 21

when is ideal gas law not obeyed

Answer 21

temp too low
pressure too high

Question 22

average bond enthalpy

Answer 22

measurement of strength in covalent bond. average amount of energy needed to break a specific type of bond. measured over a wide variety of different molecules

Question 23

metal + acid

Answer 23

salt and hydrogen

Question 24

metal oxide and acid

Answer 24

salt and water

Question 25

metal hydroxide and acid

Answer 25

salt and water

Question 26

metal carbonate and acid

Answer 26

salt and CO2 and water

Question 27

making up standard solution

Answer 27

1 weigh out precise amount of solid 2 dissolve in minimum water using glass rod 3 transfer to volumetric flask using a funnel 4 take rinsing of funnel breaker and rod using distilled water 5 fill up till bottom of meniscus touches scratch mark using a pipette 6 add stopper and invert.