an acid base indicator is a weak acid or weak base that exhibits a colour change as the concentration of hydrogen (H^+) or hydroxide (H^-) ions changes in an aqueous solution
1aii)
methyl-orange
1b)
i)oxidizing agent
ii)mixed anhydride
1c)
enthalpy of combustion is the heat evolved when one mole of a substance is completely burns in oxygen gas under standard conditions
1cii)
enthapy of combustion is always negetive since it involvs a rise in temperature and heat of reactants is greater than the heat of products
1d)
primary cell is a cell that cannot be re charged while secondary cell is a cell that can be recharged
1dii)
primary cell -- daniell cell
secondary cell -- lead accumulator
1e)
mole is the unit of measurement in the International System of Units (SI) for amount of substance. The unit is defined as the amount of a chemical substance which contains as many representative particles, e.g., atoms, molecules, ions, electrons, or photons, as there are atoms in 12 grams of carbon-12 (12C), the isotope of carbon with relative atomic mass
1f)
n= V=40cm^3
c= 0.40moldm^3
n=cv/1000
0.40*40/1000 = 0.016mol
[1:07PM, 4/18/2017] Lijoka CTE: 2ai)ii The periodic table arranges the elementsby periodic properties, which are recurring trends in physical and chemicalcharacteristics. ... These trends explainthe periodicity observed in the elementalproperties of atomic radius, ionization energy, electron affinity, and electronegativity.
[1:08PM, 4/18/2017] Lijoka CTE: 2aii) Electron affinity
Ionization energy
Electronegativity
[1:08PM, 4/18/2017] Lijoka CTE: 2aiii) ELECTRON AFFINITY
Electron affinity reflects the ability of an atom to accept an electron. It is the energy change that occurs when an electron is added to a gaseous atom.
Ionization energy:
Ionization energy is the energy required to remove an electron from a gaseous atom or ion. The first or initial ionization energy or Ei of an atom or molecule is the energy required to remove one mole of electrons from one mole of isolated gaseous atoms or ions.
Electronegativity:
Electronegativity is a measure of the attraction of an atom for the electrons in a chemical bond. The higher the electronegativity of an atom, the greater its attraction for bonding electrons.
[1:08PM, 4/18/2017] Lijoka CTE: 2ai)ii The periodic table arranges the elementsby periodic properties, which are recurring trends in physical and chemicalcharacteristics. ... These trends explainthe periodicity observed in the elementalproperties of atomic radius, ionization energy, electron affinity, and electronegativity.
2aii) Electron affinity
Ionization energy
Electronegativity
2aiii) ELECTRON AFFINITY
Electron affinity reflects the ability of an atom to accept an electron. It is the energy change that occurs when an electron is added to a gaseous atom.
Ionization energy:
Ionization energy is the energy required to remove an electron from a gaseous atom or ion. The first or initial ionization energy or Ei of an atom or molecule is the energy required to remove one mole of electrons from one mole of isolated gaseous atoms or ions.
Electronegativity:
Electronegativity is a measure of the attraction of an atom for the electrons in a chemical bond. The higher the electronegativity of an atom, the greater its attraction for bonding electrons.
[1:08PM, 4/18/2017] Lijoka CTE: 2b) relative molecular mass is the sum of all the relative atomic masses of the atoms in a molecule; the ratio of the average mass per molecule of a specified isotopic composition of a substance to one-twelfth the mass of an atom of carbon-12 M r, r.m.m.
[1:14PM, 4/18/2017] Lijoka CTE: 3a) (i)the
standard electrode potentiaqlof the meteal
ion on the hydrogen scale is the potential
difference (in volts) which exists between
the metallic electrode and the standard
hydrogen elctrode. (ii) -position of ions in
the electrochemical
3b) if a copper
plate is
immersed in a solution of
copper(vi) tetraoxosulphate
solution, Cu (2+) ion acquires
two electrons from the copper
plate to become deposited as
neutral metallic copper on the
plate. a potential difference is
setup betwwen the copper
metal and the solution
containing ions. Cu(2+)(aq)+2e
(-)=>Cu(s) (3c) Cu(2+)+ 2e
(-)=>Cu 2*96500=64g Q=it
Q=0.2*35*35*60 Q=420C
2*96500=64 420 columbs=64
mass=(64*420)/(2*96500)
=0.139g
(3d) (i)-it doesnt
participate in reaction -its mass
does not change in reaction -it
alters the rate of chemical
reaction (ii) i- hydrogenation of
oil.
1c) (i) Nuclear fission is the disintegration of heavy nuclei to form light nuclei (ii) Nuclear fussion is the combination of light nuclei to form heavy nuclei
(1d) (i)a. alpha -Ray b. beta -Ray c. Gamma- Ray (ii) (I.) alpha < beta < gamma increasing in penetrating power (II.)gamma < beta < alpha increasing in ionizing power.
(2b) (II) form and complete the table for- Indicator(methyl orange) - colour in acidic medium(red) -colour in basic medium (yellow) for- Indicator (phenolphthalein) - colour in acidic medium (colurless) -colour in basic medium (pink
3b) if a copper plate is immersed in a solution of copper(vi) tetraoxosulphate solution, Cu (2+) ion acquires two electrons from the copper plate to become deposited as neutral metallic copper on the plate. a potential difference is setup betwwen the copper metal and the solution containing ions. Cu(2+)(aq)+2e(-)=>Cu(s)
(3c) Cu(2+)+ 2e(-)=>Cu 2*96500=64g Q=it Q=0.2*35*35*60 Q=420C 2*96500=64 420 columbs=64 mass=(64*420)/(2*96500) =0.139g
(3d) (i)-it doesnt participate in reaction -its mass does not change in reaction -it alters the rate of chemical reaction (ii) i- hydrogenation of oil.
8ai)Each
successive member of a
homologous series differ by
~CH2~group.Members of a
homologous series show
similar chemical
properties.7 WAEC CHEMISTRY ANSWER NOW AVAILABLE
Fgg
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