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The set – up below was used to (electrolyse roller lead (II) iodide. i) State the observation that was made at the anode during the electrolysis.Give...
(Solved)
The set – up below was used to (electrolyse roller lead (II) iodide.
i) State the observation that was made at the anode during the electrolysis.
Give a reason for your answer.(2mk)
ii) A current of 0.5 A was passed for two hours. Calculate the mass of lead
that was deposited (pb = 1F = 9,500C)
Date posted:
June 24, 2019
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Answers (1)
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Give one advantage and one disadvantage of dry cells.
(Solved)
Give one advantage and one disadvantage of dry cells.
Date posted:
June 24, 2019
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Answers (1)
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State the observation made when excess pentane is reacted with bromine gas
(Solved)
State the observation made when excess pentane is reacted with bromine gas
Date posted:
June 24, 2019
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Answers (1)
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Oleum (H2S2O7) is an intermediate product in the industrial manufacture of sulphuric
acid
(a) How is oleum converted into sulphuric acid?
(b) Give one use of sulphuric...
(Solved)
Oleum (H2S2O7) is an intermediate product in the industrial manufacture of sulphuric
acid
(a) How is oleum converted into sulphuric acid?
(b) Give one use of sulphuric acid
Date posted:
June 24, 2019
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Answers (1)
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When excess dilute hydrochloric acid was added to sodium , 960cm3 of sulphur (IV)
oxide gas was produced. Calculate the mass of sodium sulphite that was...
(Solved)
When excess dilute hydrochloric acid was added to sodium , 960cm3 of sulphur (IV)
oxide gas was produced. Calculate the mass of sodium sulphite that was used. (molar
mass of sodium = 126 g and molar gas volume= 24000cm3
Date posted:
June 24, 2019
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Answers (1)
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Hydrogen reacts with hexane to form hexane. Calculate the volume or hydrogen
gas required to convert 42g of hexane to hexane at S.T.P ( C=12.0, H=1.0,...
(Solved)
Hydrogen reacts with hexane to form hexane. Calculate the volume or hydrogen
gas required to convert 42g of hexane to hexane at S.T.P ( C=12.0, H=1.0, molar
gas volume at S.T.P is = 22.4 litres)
Date posted:
June 24, 2019
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Answers (1)
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State one use of hexane.
(Solved)
State one use of hexane.
Date posted:
June 24, 2019
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Answers (1)
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Describe one chemical test that can be used to distinguish between hexane and hexane
(Solved)
Describe one chemical test that can be used to distinguish between hexane and hexane
Date posted:
June 24, 2019
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Answers (1)
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Name the product formed when methanol reacts with methanoic acid
(Solved)
Name the product formed when methanol reacts with methanoic acid
Date posted:
June 24, 2019
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Answers (1)
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Write the equation for the reaction between methanoic acid and aqueous sodium hydroxide
(Solved)
Write the equation for the reaction between methanoic acid and aqueous sodium hydroxide
Date posted:
June 24, 2019
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Answers (1)
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In the preparation of a bleaching agent (Sodium hypochlorite), Excess chlorine gas was
bubbled into 15 litres of cold 2 m sodium hydroxide
(i) Write an equation...
(Solved)
In the preparation of a bleaching agent (Sodium hypochlorite), Excess chlorine gas was
bubbled into 15 litres of cold 2 m sodium hydroxide
(i) Write an equation for the reaction between chlorine gas and cold dilute sodium
Hydroxide
(ii) Calculate the:
Number of moles of sodium hydroxide used
Mass in kilograms of the sodium hypochlorite produced = 1. 1175
Date posted:
June 24, 2019
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Answers (1)
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What method can be used to separate a mixture of ethanol and propanol?
(Solved)
What method can be used to separate a mixture of ethanol and propanol?
Date posted:
June 24, 2019
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Answers (1)
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Name one suitable drying agent for ammonia gas.
(Solved)
Name one suitable drying agent for ammonia gas.
Date posted:
June 24, 2019
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Answers (1)
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When excess lead nitrate solution was added to a solution containing sodium chloride,
the precipitate formed was found to weigh 5.56 g. Determine the amount of...
(Solved)
When excess lead nitrate solution was added to a solution containing sodium chloride,
the precipitate formed was found to weigh 5.56 g. Determine the amount of sodium
chloride in the solution ( Pb = 207, Cl = 35.5 Na = 23)
PbXO3(aq) + 2NaCl (aq) → PbCI2 + NaNO3 (aq) (l)
Date posted:
June 24, 2019
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Answers (1)
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When carbon dioxide gas was passed through aqueous calcium hydroxide a white
suspension was formed
(a) Write an equation for the reaction that took place
(b) State and...
(Solved)
When carbon dioxide gas was passed through aqueous calcium hydroxide a white
suspension was formed
(a) Write an equation for the reaction that took place
(b) State and explain the changes that would occur when carbon dioxide gas is bubbled
through the white suspension
Date posted:
June 24, 2019
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Answers (1)
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The following two tests were carried out on chlorine water contained in two test tubes
a) A piece of blue flower was dropped into the first...
(Solved)
The following two tests were carried out on chlorine water contained in two test tubes
a) A piece of blue flower was dropped into the first – tube. Explain why the flower
was bleached
(b) The second test- tube was corked and exposed to sunlight after a few days, it was
found to contain a gas that rekindled a glowing splint. Write an equation for the
reaction which produced the gas
Date posted:
June 24, 2019
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Answers (1)
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In an experiment to study the rate for reaction between duralumin (an alloy of aluminium,
magnesium and copper) and hydrochloric acid, 0.5g of the alloy were...
(Solved)
In an experiment to study the rate for reaction between duralumin (an alloy of aluminium,
magnesium and copper) and hydrochloric acid, 0.5g of the alloy were reacted with excess
4M hydrochloric acid. The data in the table below was recoded.
Use it to answer the questions that follow.
a) i) On the grid provided, plot a graph of total volume of gas produced (vertical axis)
again time.
ii) From the graph, determine the volume of gas produced at the end of 2 ½ minutes.
b) Determine the rate of reaction between the 3rd and 4th minute.
c) Give a reason why some solid remained at the end of the experiment
d) Given that 2.5cm3 of the total volume of the gas was from the reaction between
magnesium and aqueous hydrochloric acid, calculate the percentage mass of aluminium
present in 0.5g of the alloy.
(Al = 27.0 and Molar gas volume = 24,000cm3 at 298k)
e) State two properties of duralumin that make it more suitable than aluminium in aeroplane
construction.
Date posted:
June 24, 2019
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Answers (1)
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When a sample of concentrated sulphuric acid was left in an open beaker in a room for
two days, the volume was found to have increased...
(Solved)
When a sample of concentrated sulphuric acid was left in an open beaker in a room for
two days, the volume was found to have increased slightly
a) What property of concentrated sulphuric acid was left in an open beaker in a room
for two days, the volume was found to have increased slightly.
b) State one use of concentrated sulphuric acid that depends on the property named
above.
Date posted:
June 24, 2019
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Answers (1)
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A weighed sample of crystalline sodium carbonate (Na2CO3. H2O) was heated in a
crucible until there was no further change in mass.
Calculate the number of moles...
(Solved)
A weighed sample of crystalline sodium carbonate (Na2CO3. H2O) was heated in a
crucible until there was no further change in mass.
Calculate the number of moles (n) of the water of crystallization
Date posted:
June 24, 2019
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Answers (1)
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At 298K and 1 atmosphere, graphite changes into diamond according to the equation:
C (graphite) ? C(diamond); ?=2.9 kJmo-1
In the space provided, sketch a simple energy...
(Solved)
At 298K and 1 atmosphere, graphite changes into diamond according to the equation:
C (graphite) → C(diamond); △=2.9 kJmo-1
In the space provided, sketch a simple energy level diagram for the above change.
Date posted:
June 24, 2019
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Answers (1)