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- 100 g of a radioactive substance was reduced to 12.5 g in 15.6 years. Calculate the half –
life of the substance.(Solved)
100 g of a radioactive substance was reduced to 12.5 g in 15.6 years. Calculate the half –
life of the substance.
Date posted: June 24, 2019. Answers (1)
- Ethane, C2H2 is another compound found in crude oil.
One mole of ethane was reacted with one mole of hydrogen chloride gas and a
product p1 and...(Solved)
Ethane, C2H2 is another compound found in crude oil.
One mole of ethane was reacted with one mole of hydrogen chloride gas and a
product p1 and was formed. P1 was then reacted with excess hydrogen gas to
form p2. Draw the structures p1 and p2.
Date posted: June 24, 2019. Answers (1)
- Under certain conditions, hexane can be converted to two products.
The formula of one of the products is C3H3
Write the formula of the other product(Solved)
Under certain conditions, hexane can be converted to two products.
The formula of one of the products is C3H3
Write the formula of the other product
Date posted: June 24, 2019. Answers (1)
- Determine the molar concentration of potassium nitrate at 150C
(Assume there is no change in density of water at this temperature)
(K = 39. 0; N=...(Solved)
Determine the molar concentration of potassium nitrate at 150C
(Assume there is no change in density of water at this temperature)
(K = 39. 0; N= 14.0; O = 16.0)
Date posted: June 24, 2019. Answers (1)
- Ammonia sulphate is a fertilizer produced by passing ammonia gas into concentrated
sulphuric acid.
(i) Write the equation for the reaction
(ii) Calculate the mass in Kg of...(Solved)
Ammonia sulphate is a fertilizer produced by passing ammonia gas into concentrated
sulphuric acid.
(i) Write the equation for the reaction
(ii) Calculate the mass in Kg of sulphuric acid required to produce 25kg of the
fertilizer (S= 32.0; O= 16.0; N = 1.0)
Date posted: June 24, 2019. Answers (1)
- Chlorine gas is prepared by reacting concentrated hydrochloric acids with
manganese (iv) oxide.
i) Write the equation for reaction between concentrated hydrochloric acid
and manganese (iv) oxide.
ii)...(Solved)
Chlorine gas is prepared by reacting concentrated hydrochloric acids with
manganese (iv) oxide.
i) Write the equation for reaction between concentrated hydrochloric acid
and manganese (iv) oxide.
ii) What is the role of manganese (Iv) oxide in this reaction
Date posted: June 24, 2019. Answers (1)
- i) Iron (II) chloride reacts with chlorine gas to form substance E.
Identify substance E
ii) During the reaction in (i) above,6.30g of iron chloride were converted...(Solved)
i) Iron (II) chloride reacts with chlorine gas to form substance E.
Identify substance E
ii) During the reaction in (i) above,6.30g of iron chloride were converted to
8.06 of substance E. Calculate the volume of chlorine used.
(Cl = 35.5, Molar gas volume at room temperature = 24000cm3, Fe =56
Date posted: June 24, 2019. Answers (1)
- Draw and name the structure of the compound formed when excess chlorine gas
is reacted with ethane gas.(Solved)
Draw and name the structure of the compound formed when excess chlorine gas
is reacted with ethane gas.
Date posted: June 24, 2019. Answers (1)
- Carbon dioxide can be dissolved in water under pressure to make an acidic solution.
a) What is meant by an acidic solutions?
b) aqueous lead (II) nitrate...(Solved)
Carbon dioxide can be dissolved in water under pressure to make an acidic solution.
a) What is meant by an acidic solutions?
b) aqueous lead (II) nitrate reacts with the acidic solution to form a precipitate.
Write anionic equation for the reaction
Date posted: June 24, 2019. Answers (1)
- Name one apparatus that may be used to measure the volume of hydrogen gas produced.(Solved)
Name one apparatus that may be used to measure the volume of hydrogen gas produced.
Date posted: June 24, 2019. Answers (1)
- Astrip of metal Q was dipped into a solution of copper (II) sulphate and allowed to stand
overnight. Give that
a) State the observations which were made
b)...(Solved)
Astrip of metal Q was dipped into a solution of copper (II) sulphate and allowed to stand
overnight. Give that
a) State the observations which were made
b) Give a reason for your answer in (a) above.
Date posted: June 24, 2019. Answers (1)
- When X cm3 of a solution of 0.5m magnesium carbonate was 8.4g.
a) Write the ionic equation for the reaction that took place
b) Calculate the value...(Solved)
When X cm3 of a solution of 0.5m magnesium carbonate was 8.4g.
a) Write the ionic equation for the reaction that took place
b) Calculate the value of X. (C = 12.0, Mg 24.0; 016.0
Date posted: June 24, 2019. Answers (1)
- Draw the structure of the smallest repeating unit of a polyvinyl chloride(Solved)
Draw the structure of the smallest repeating unit of a polyvinyl chloride
Date posted: June 24, 2019. Answers (1)
- Draw the structural formula of the third member of the homologous series of ethyne.(Solved)
Draw the structural formula of the third member of the homologous series of ethyne.
Date posted: June 24, 2019. Answers (1)
- State how burning can be used to distinguish between ethane and ethyne.
Explain your answer.(Solved)
State how burning can be used to distinguish between ethane and ethyne.
Explain your answer.
Date posted: June 24, 2019. Answers (1)
- 1.2 litres of hydrogen gas produced at room temperature and pressure when
3.27g of zinc was used. Determine the relative atomic mass of zinc.(Molar gas
volume is...(Solved)
1.2 litres of hydrogen gas produced at room temperature and pressure when
3.27g of zinc was used. Determine the relative atomic mass of zinc.(Molar gas
volume is 24 litres)
Date posted: June 24, 2019. Answers (1)
- 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. Answers (1)
- Give one advantage and one disadvantage of dry cells.(Solved)
Give one advantage and one disadvantage of dry cells.
Date posted: June 24, 2019. Answers (1)
- Element A is the same group of the periodic table as chlorine.
Write the formula of the compound formed when A reacts with potassium metal.(Solved)
Element A is the same group of the periodic table as chlorine.
Write the formula of the compound formed when A reacts with potassium metal.
Date posted: June 24, 2019. Answers (1)
- 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. Answers (1)