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Melting points of all group (i) elements is dependent on the strength of the metallic bond. In metallic bonding, the group (i) cations in the metallic lattice are attracted to the delocalised electrons. Down the group, the number of delocalised electrons and the charge on each cation remains the same at +1 but the cationic radius increases so the attraction between the cations and the electrons in the lattice get weaker down the group and so does the strength of the metallic bond.
hingboe answered the question on July 17, 2019 at 09:23
- RCOO- Na+ and RC6H5SO3- Na+, represent two cleansing agents where R is a long hydrocarbon chain.
Write the formulae of the salts that would be...(Solved)
R COO─ Na+ and RC6H5SO3─ Na+, represent two cleansing agents where R is a long hydrocarbon chain.
Write the formulae of the salts that would be formed when each of these cleansing agents is added to water containing calcium ions.
Date posted: June 24, 2019. Answers (1)
- State two similarities between rusting and combustion. (Solved)
State two similarities between rusting and combustion.
Date posted: June 24, 2019. Answers (1)
- In an experiment to determine the percentage purity of the sample of
sodium carbonate produced in the Solvay process, 2.15 g of the
sample reacted completely with...(Solved)
In an experiment to determine the percentage purity of the sample of
sodium carbonate produced in the Solvay process, 2.15 g of the
sample reacted completely with 40.0cm3 of 0.5 M sulphuric acid.
I calculate the number of moles of sodium carbonate that
reacted.
II Determine the percentage of sodium carbonate in the
sample. (Na= 23.0, C= 12.0, O = 16.0)
Date posted: June 24, 2019. Answers (1)
- 0.84 g of aluminium reacted completely with chlorine gas.
Calculate the volume of chlorine gas used (Molar gas volume is 24dm3, al = 27).(Solved)
0.84 g of aluminium reacted completely with chlorine gas.
Calculate the volume of chlorine gas used (Molar gas volume is 24dm3, al = 27).
Date posted: June 24, 2019. Answers (1)
- When aluminium oxide was electrolysed, 1800kg of aluminium metal were
obtained.
a) Write equation for the formation of aluminium metal
b) Calculate the quantity of electricity in faradays...(Solved)
When aluminium oxide was electrolysed, 1800kg of aluminium metal were
obtained.
a) Write equation for the formation of aluminium metal
b) Calculate the quantity of electricity in faradays used (Al=27)
Date posted: June 24, 2019. Answers (1)
- A sample of biogas contains 35.2% by mass of methane. A biogas cylinder
contains 5.0 kg of the gas.
Calculate the;
(i) Number of moles of methane in...(Solved)
A sample of biogas contains 35.2% by mass of methane. A biogas cylinder
contains 5.0 kg of the gas.
Calculate the;
(i) Number of moles of methane in the cylinder. (Molar mass of methane=16)
(ii) Total volume of carbon (IV) oxide produced by the combustion of methane in the
cylinder (Molar gas Volume=24.0 dm-3+ at room temperature and pressure).
Date posted: June 24, 2019. Answers (1)
- In an experiment to determine the percentage of magnesium hydroxide in an anti-acid, a
solution containing 0.50 g of the anti-acid was neutralized by 23.0 cm3...(Solved)
In an experiment to determine the percentage of magnesium hydroxide in an anti-acid, a
solution containing 0.50 g of the anti-acid was neutralized by 23.0 cm3 of 0.010m
hydrochloric acid (Relative formula mass of magnesium hydroxide =58)
a) Mass of magnesium hydroxide in the anti-acid;
b) Percentage of magnesium hydroxide in the anti-acid
Date posted: June 24, 2019. Answers (1)
- When 1.08g of aluminum foil were heated in a stream of chlorine gas, the mass of the
product formed was 3.47 g
Calculate the:
(i) Maximum mass of...(Solved)
When 1.08g of aluminum foil were heated in a stream of chlorine gas, the mass of the
product formed was 3.47 g
Calculate the:
(i) Maximum mass of the product formed if chlorine was in excess;
(Al= 27; Cl = 35.5)
(ii) Percentage yield of the product formed
Date posted: June 24, 2019. Answers (1)
- Calculate the mass of nitrogen present if a 25kg bag contained pure
ammonium phosphate, (NH4)2 HPO4. (N = 14.0, H=1.0, P = 31.0, O =16.0(Solved)
Calculate the mass of nitrogen present if a 25kg bag contained pure
ammonium phosphate, (NH4)2 HPO4. (N = 14.0, H=1.0, P = 31.0, O =16.0
Date posted: June 24, 2019. Answers (1)
- The relative molecular mass of one of the fullerenes is 720. What is the
molecular formula of this fullerene? (C=12.00(Solved)
The relative molecular mass of one of the fullerenes is 720. What is the
molecular formula of this fullerene? (C=12.00
Date posted: June 24, 2019. Answers (1)
- Compounds A and B have the same molecular formula C3H6O2. Compound A
liberates carbon (IV) oxide on addition of aqueous sodium carbonate while
compound B does not....(Solved)
Compounds A and B have the same molecular formula C3H6O2. Compound A
liberates carbon (IV) oxide on addition of aqueous sodium carbonate while
compound B does not. Compound B has a sweet smell. Draw the possible
structures of:
(i) Compound A
ii) Compound B
Date posted: June 24, 2019. Answers (1)
- 6.84g of aluminium sulphate were dissolve in 150cm3 of water. Calculate the molar
concentration of the sulphate ions in the solution. (Relative formula mass of aluminium
sulphate...(Solved)
6.84g of aluminium sulphate were dissolve in 150cm3 of water. Calculate the molar
concentration of the sulphate ions in the solution. (Relative formula mass of aluminium
sulphate is 342)
Date posted: June 24, 2019. Answers (1)
- The relative formula mass of a hydrocarbon is 58. Draw and name two possible
structures of the hydrocarbon (C=12.0; H=1.0)(Solved)
The relative formula mass of a hydrocarbon is 58. Draw and name two possible
structures of the hydrocarbon (C=12.0; H=1.0)
Date posted: June 24, 2019. Answers (1)
- The volume of a sample of nitrogen gas at a temperature of 291 K and 1.0x105
Pascal’s was 3.5 x 10-2m3. Calculate the temperature at which...(Solved)
The volume of a sample of nitrogen gas at a temperature of 291 K and 1.0x105
Pascal’s was 3.5 x 10-2m3. Calculate the temperature at which the volume of the
gas would be 2.8 x 10-2m3 at 1.0 x 105 Pascal.
Date posted: June 24, 2019. Answers (1)
- 15.0cm3 of ethanoic acid (CH3COOH) was dissolved in water to make 500cm3 of
solution. Calculate the concentration of the solution in moles per litre.
(C=12.0;H=1.0;O=16.0; density of...(Solved)
15.0cm3 of ethanoic acid (CH3COOH) was dissolved in water to make 500cm3 of
solution. Calculate the concentration of the solution in moles per litre.
(C=12.0;H=1.0;O=16.0; density of ethanoic acid is 1.05 g/cm3)
Date posted: June 24, 2019. Answers (1)
- When 3 litres of chlorine gas were completely reacted with element D, 11.875 g of the product were formed. Determine the relative atomic mass of element D.(Atomic mass...(Solved)
When 3 litres of chlorine gas were completely reacted with element D, 11.875g
of the product were formed. Determine the relative atomic mass of element D.
(Atomic mass of chlorine = 35.5; molar gas volume = 24litres).
Date posted: June 24, 2019. Answers (1)
- During the electrolysis, a current of 0.72A was passed through the electrolyte for 15
munites.Calculate the volume of gas produced at the anode.(1 Faraday = 96...(Solved)
During the electrolysis, a current of 0.72A was passed through the electrolyte for 15
munites.Calculate the volume of gas produced at the anode.(1 Faraday = 96 500
coulombs; molar gas volume is 24000cm3 at room temperature).
Date posted: June 24, 2019. Answers (1)
- When 94.5g of hydrated Barium hydroxide Ba(OH)2 . XH2O were heated to a constant mass 51.3g of anhydrous Barium hydroxide. Determine the empirical formula of...(Solved)
When 94.5g of hydrated Barium hydroxide Ba(OH)2 . XH2O were heated to a constant mass 51.3g of anhydrous Barium hydroxide. Determine the empirical formula of the hydrated Barium hydroxide. (Ba= 137.0, O = 16.0, H = 1.0).
Date posted: June 24, 2019. Answers (1)
- Draw and name two isomers of butane.(Solved)
Draw and name two isomers of butane.
Date posted: June 24, 2019. Answers (1)
- During electrolysis of aqueous copper (II) sulphate, 144750 coulombs of electricity were
used.
Calculate the mass of copper metal that was obtained
Cu = 64 ; 1 Faraday...(Solved)
During electrolysis of aqueous copper (II) sulphate, 144750 coulombs of electricity were
used.
Calculate the mass of copper metal that was obtained
Cu = 64 ; 1 Faraday = 96500 coulombs)
Date posted: June 24, 2019. Answers (1)