NICE MAN :bomb: Chemistry Theory Answers
1a )
i) they are relatively of low cost
ii )They have high heat resistance
1bi )
draw the structure
H H
H - C- C- H
Br Br bromoethane
1bii )
bromoethene
1c )
Because Ethanol is less denser than water
1di )
Le Châtelier 's principle , states that if a system in equilibrium is disturbed by changes in determining factors , such as temperature , pressure, and concentration of components, the system will tend to shift its equilibrium position so as to counteract the effect
1dii )
i) F2 +2NaOH - - - - - > NaOF +NaF +H 20
ii )Cl 2+2 NaOH- - - - - > NaOCl + NaCl+ H 20
1dii )
i) K2SO3 has been oxidized
ii )Ag ^ 2+ has been oxidized
1e )
dynamic equilibrium is a steady state
reached when a reversible reaction occurs at the same rate in both directions and has an unchanging ratio of products and reactants .
1f)
diagrams
(k )** ( k )** (2 ) (k )** ( k )**
1g )
because it attains equilibrium at very fast rate
1hi )
i) electrovalent bonding .
ii )covalent bonding
1hii )
Aufbau principle states that hypothetically , electrons orbiting one or more atoms fill the lowest available
energy levels before filling higher levels ( e . g. , 1 s before 2 s ) . In this way , the electrons of an atom , molecule , or ion harmonize into the most stable electron configuration possible .
1i )
The outer electron in aluminium is in a p sub- level . This is higher in energy than the outer electron in magnesium , which is in an s sub - level , so less energy is needed to remove it .
1j )
i) Substitution
ii )addition
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2ai )
Vander waal 's force are weak intermolecular gases at room temperature .
2aii )
- Electronegativity difference
- Ionization energy
2aiii)
- Ionization energy
- Electron affinity
2b )
C- F and C- O
C- N and C- H - O and C- N and C- F and C- O
2ci)
- Be = 1S ^ 22 S ^ 2
4Mg =1 S ^ 22 S ^ 22 P^ 63 S ^ 2
They both have the same number of electron in the outermost shell
2cii )
Mg ^ 2+ - > Na^ + - > Ne
The size of positive ion is less than that of the neutral atom
2di )
Transition element are element in d- orbital of the periodic table in which the 3d orbital is partially or incompletely filled
2dii )
Because they can loose electron from either th e 3d or 4s orbital
2diii)
It is used for making alloy
2div)
It is used in electroplating and galvanizing to make electrical cable
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3ai )
Crystallisation is a separation technique that is used to separate. a solid that has dissolved in a liquid and made a solution. The solution is warmed in an open container, allowing the solvent to evaporate , leaving a saturated solution.
3aii )
Evaporation is the process of a
substance in a liquid state changing to a
gaseous state due to an increase in temperature and / or pressure.
3aiii)
Filtration is any of various mechanical , physical or biological operations that separate solids from fluids ( liquids or gases) by adding a medium through which only the fluid can pass .
3bi )
i) Their Melting and Boiling Points increases down the group
ii )Their atomic Radius increases down the group
iii ) Their Ionization Energy: decreases down the group
3bii )
4NaOH( aq )+ 2F 2( aq) - > 4 NaF( aq )+ O2 (g ) +2H 2O (l )
Cl2 (g )+ 2NaOH( aq )- > NaOCl (aq ) +NaCl( aq )
+NaCl (aq ) +H 2 O( l)
3ci)
Gas is a state of matter while vapour is
the gaseous state of substance in equilibrium with its liquid or solid state
3cii )
Normal temperature and pressure
3di )
Mg (s )+ Cl2( g) - > MgCl 2( s )
3dii )
n= mass/ molarmass
n= 24/ 35. 5
n= 1. 2/ 24
n= 0. 05
number of moles = volume used/ molar
volume 0. 05 =V/ 22. 4
V=1 . 12dm ^ 3
3e )
- Atomic number is the number of protons present in an atomic nucleus of the element
- Mass number of an element is the sum of the protons and neutrons in the atomic nucleus of the element
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4ai )
Hard water is water which does not lather readily with soap . Hard water is formed when water percolates through deposits of limestone and chalk which are largely made up of calcium and magnesium carbonates .
4ii )
- Temporary hardness : Ca( HCO3 )2
- Permanent hardness : Na2 C03
4aiii)
- By using chemicals like caustiic soda .
- By using permutot OR zeolite
4bi )
i) coagulation
ii ) sedimentation
iii ) filtration
iv ) chlorination/ disinfection
4bii )
i) Sodium chloride
ii ) Potassium chloride
iii ) Chlorine dioxide
4ci)
Solubility is the property of a solid , liquid , or gaseous chemical substance called solute to dissolve in a solid , liquid