- Explain how a catalyst affects the following in a chemical reaction.(i) The enthalpy change. (ii) The activation energy. (iii) Chemical equilibrium(Solved)
Explain how a catalyst affects the following in a chemical reaction.
(i) The enthalpy change.
(ii) The activation energy.
(iii) Chemical equilibrium.
Date posted: November 5, 2017.
- Give a reason why it is preferred to use warm water to cold water when collecting oxygen gas(Solved)
Give a reason why it is preferred to use warm water to cold water when collecting oxygen gas
Date posted: November 5, 2017.
- State the observation made when hydrogen sulphide gas is bubbled through aqueous lead (II) nitrate solution(Solved)
1.(a) State the observation made when hydrogen sulphide gas is bubbled through aqueous lead (II) nitrate solution.
(b) Write an ionic equation for the reaction above.
Date posted: November 5, 2017.
- Explain why the ability of temporary hard water to conduct electricity falls when water is boiled, but it does not fall when temporary hardness is removed...(Solved)
Explain why the ability of temporary hard water to conduct electricity falls when water is boiled, but it does not fall when temporary hardness is removed by addition of washing soda
Date posted: November 5, 2017.
- The melting point of phosphorous trichloride is -91°C while that of sodium chloride is 801°C. In terms of structure and bonding explain the difference in...(Solved)
The melting point of phosphorous trichloride is -91°C while that of sodium chloride is 801°C. In terms of structure and bonding explain the difference in the melting point
Date posted: November 5, 2017.
- Describe how a solid sample of barium sulphate can be prepared starting with copper (II) oxide(Solved)
Describe how a solid sample of barium sulphate can be prepared starting with copper (II) oxide
Date posted: November 5, 2017.
- Pure nitric (V) acid is colourless but the products in the laboratory preparation is usually yellow. Explain(Solved)
Pure nitric (V) acid is colourless but the products in the laboratory preparation is usually yellow. Explain
Date posted: November 5, 2017.
- Nitric (V) acid may be prepared in the laboratory by the action of concentrated sulphuric (VI) acid on a suitable nitrate and distilling OFF the...(Solved)
Nitric (V) acid may be prepared in the laboratory by the action of concentrated sulphuric (VI) acid on a suitable nitrate and distilling OFF the nitric (V) acid.
(a) Why is the apparatus consisting of glass desirable
Date posted: November 5, 2017.
- State two properties of copper that make it suitable for making ornaments(Solved)
State two properties of copper that make it suitable for making ornaments
Date posted: November 5, 2017.
- A saturated solution of a salt Y at 300C weighing 76g yielded 34g of solid when evaporated to dryness. What is the solubility of the...(Solved)
A saturated solution of a salt Y at 300C weighing 76g yielded 34g of solid when evaporated to dryness. What is the solubility of the salt at 300C
Date posted: November 5, 2017.
- Explain why the second ionization energy is higher than the first ionization energy(Solved)
Explain why the second ionization energy is higher than the first ionization energy
Date posted: November 5, 2017.
- Define second ionisation energy(Solved)
Define second ionisation energy
Date posted: November 5, 2017.
- Give one industrial use of chlorine gas(Solved)
Give one industrial use of chlorine gas
Date posted: November 5, 2017.
- Apart from manganese (IV) oxide, give the formula of any two compound that can be used in the preparation of chlorine(Solved)
Apart from manganese (IV) oxide, give the formula of any two compound that can be used in the preparation of chlorine
Date posted: November 5, 2017.
- A student from Ikerege Secondary School poured accidentally concentrated sulphuric acid on his brown sugar.
(i) State and explain the observation made(Solved)
A student from Ikerege Secondary School poured accidentally concentrated sulphuric acid on his brown sugar.
(i) State and explain the observation made
Date posted: November 5, 2017.
- A mixture contains ammonium chloride, silver chloride and lead (II) chloride. Describe how each of the substance can be obtained from the mixture(Solved)
A mixture contains ammonium chloride, silver chloride and lead (II) chloride. Describe how each of the substance can be obtained from the mixture
Date posted: November 5, 2017.
- Name one reagent that can be used to distinguish between Al3+ and Zn2+ ions in solution and state what would be observed if each of...(Solved)
Name one reagent that can be used to distinguish between Al3+ and Zn2+ ions in solution and state what would be observed if each of the ions is treated with the reagent you have named.
Date posted: November 4, 2017.
- Flower extracts are often used as indicators in the laboratory. State one disadvantage of using flower extracts as indicators(Solved)
Flower extracts are often used as indicators in the laboratory. State one disadvantage of using flower extracts as indicators
Date posted: November 4, 2017.
- Explain the effect of the by-product of roasting process of zinc ores on the environment(Solved)
Explain the effect of the by-product of roasting process of zinc ores on the environment
Date posted: November 4, 2017.
- Name the reducing agent used in the furnace during extraction of zinc(Solved)
Name the reducing agent used in the furnace during extraction of zinc
Date posted: November 4, 2017.
- Zinc is extracted from calamine, name another ore used to extract zinc(Solved)
Zinc is extracted from calamine, name another ore used to extract zinc
Date posted: November 4, 2017.
- State and explain the observation made when coloured flowers are placed into a gas jar full of chlorine gas(Solved)
State and explain the observation made when coloured flowers are placed into a gas jar full of chlorine gas
Date posted: November 4, 2017.
- (a) During the extraction of Aluminium, the oxide of metal is dissolved in Molten cryolite before it is electrolysed. Explain. (b) Giving reasons, state two uses...(Solved)
(a) During the extraction of Aluminium, the oxide of metal is dissolved in Molten cryolite before it is electrolysed. Explain.
(1mk)
(b) Giving reasons, state two uses of Aluminium metal
Date posted: November 4, 2017.
- Explain why Hydrogen Sulphide is a gas at room temperature while water is liquid at room temperature(Solved)
Explain why Hydrogen Sulphide is a gas at room temperature while water is liquid at room temperature
Date posted: November 4, 2017.
- State and explain the observations made when concentrated nitric (V) acid is added to copper turnings(Solved)
State and explain the observations made when concentrated nitric (V) acid is added to copper turnings
Date posted: November 4, 2017.
- Explain how the rate of the reaction between lead and nitric (V) acid would be affected if the temperature of the reaction mixture was lowered.(Solved)
Explain how the rate of the reaction between lead and nitric (V) acid would be affected if the temperature of the reaction mixture was lowered.
Date posted: November 4, 2017.
- Name two raw materials required in the manufacture of Sodium carbonate(Solved)
Name two raw materials required in the manufacture of Sodium carbonate
Date posted: November 4, 2017.
- What would be observed if blue litmus paper is dipped in chlorine water? Explain(Solved)
What would be observed if blue litmus paper is dipped in chlorine water? Explain
Date posted: November 4, 2017.
- Chlorine gas dissolved in distilled water to form chlorine water (a) Name the compounds present in the chlorine water(Solved)
Chlorine gas dissolved in distilled water to form chlorine water
(a) Name the compounds present in the chlorine water
(b) What would be observed if blue litmus paper is dipped in chlorine water? Explain.
Date posted: November 4, 2017.
- A student was asked to determine the percentage of zinc metal in a mixture of zinc metal and zinc oxide. He reacted the mixture with...(Solved)
A student was asked to determine the percentage of zinc metal in a mixture of zinc metal and zinc oxide. He reacted the mixture with excess hydrochloric acid and accurately collected the gas evolved, which was then used to calculate the amount of zinc in the mixture.
(a) Name the gas that was evolved
(b) Apart from the reaction liberating the gas write a balanced equation for the other reaction that took place.
(c) Why would dilute nitric acid not suitable for this reaction?
Date posted: November 4, 2017.