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a) Presence of calcium hydrogen carbonate or magnesium hydrogen carbonate
b) Water vaporizes and distils off leaving behind ions that cause hardness
johnmulu answered the question on February 10, 2017 at 14:20
- A student was supplied with a colourless liquid suspected to be water (i) Describe one chemical test that could have been used to show that the liquid was water(Solved)
A student was supplied with a colourless liquid suspected to be water
i) Describe one chemical test that could have been used to show that the liquid was water
ii) How could it have been shown that the liquid was pure water
Date posted: February 10, 2017. Answers (1)
- When solid magnesium carbonate was added to a solution of hydrogen chloride in methylbenzene, there was no apparent reaction(Solved)
When solid magnesium carbonate was added to a solution of hydrogen chloride in methylbenzene, there was no apparent reaction. On addition of water to the resulting mixture, there was vigorous effervescence. Explain these observations.
Date posted: February 10, 2017. Answers (1)
- State and explain one disadvantage of using hard water in boilers(Solved)
State and explain one disadvantage of using hard water in boilers.
Date posted: February 10, 2017. Answers (1)
- Give one advantage of using hard water for domestic purposes(Solved)
Give one advantage of using hard water for domestic purposes
Date posted: February 10, 2017. Answers (1)
- A bee-keeper found that when stung by a bee, application of a little solution of sodium hydrogen carbonate helped to relieve the irritation from the affected area. Explain(Solved)
A bee-keeper found that when stung by a bee, application of a little solution of sodium hydrogen carbonate helped to relieve the irritation from the affected area. Explain
Date posted: February 10, 2017. Answers (1)
- Distinguish between a strong and a weak acid. Give an example of each(Solved)
Distinguish between a strong and a weak acid. Give an example of each.
Date posted: February 10, 2017. Answers (1)
- A sample of water drawn from a river passing through an agricultural district was divided into two portions(Solved)
A sample of water drawn from a river passing through an agricultural district was divided into two portions. The first portion gave a white precipitate when acidified barium chloride was added. The second portion when warmed with aqueous sodium hydroxide gave a colourless gas which turned a moist red litmus paper blue.
i) Identify the ions present in the river water
ii) Suggest the possible source (s) of ions identified in (a) above
Date posted: February 10, 2017. Answers (1)
- Give the formula of an oxide which reacts with both dilute hydrochloric acid and hot concentrated sodium hydroxide(Solved)
a) Give the formula of an oxide which reacts with both dilute hydrochloric acid and hot concentrated sodium hydroxide
b) Give the formulae of the products formed when the oxide in (a) above reacts with excess hot concentrated sodium hydroxide.
Date posted: February 10, 2017. Answers (1)
- 90 cm3 of 0.01M calcium hydroxide were added to a sample of water containing 0.001 moles of calcium hydrogen carbonate(Solved)
90 cm3 of 0.01M calcium hydroxide were added to a sample of water containing 0.001 moles of calcium hydrogen carbonate
a) Write an equation for the reaction which took place
b) Calculate the number of moles of calcium ions in 90 cm3 of 0.01M calcium hydroxide.
c) What would be observed if soap solution was added dropwise to a sample of the water after the addition of calcium hydroxide? Give a reason.
Date posted: February 10, 2017. Answers (1)
- Write the formula of the complex ion formed in each of the reactions described below(Solved)
Write the formula of the complex ion formed in each of the reactions described below.
i) Zinc metal dissolves in hot alkaline solution
ii) Copper hydroxide dissolves in excess ammonia solution
Date posted: February 10, 2017. Answers (1)
- Give the name of each of the processes described below which takes place when the salts are exposed to air for sometimes(Solved)
Give the name of each of the processes described below which takes place when the salts are exposed to air for sometimes
i) Anhydrous copper sulphate becomes wet
ii) Magnesium chloride forms an aqueous solution
iii) Fresh crystals of sodium carbonate, Na2CO3.10H2O become covered with white powder of formula Na2CO3.H2O
Date posted: February 10, 2017. Answers (1)
- Explain the following observation. A chloride dissolves in water to form an electrolyte while the same chloride dissolves in methylbenzene to form a non-electrolyte(Solved)
Explain the following observation. A chloride dissolves in water to form an electrolyte while the same chloride dissolves in methylbenzene to form a non-electrolyte
Date posted: February 10, 2017. Answers (1)
- During an experiment, chlorine gas was bubbled into a solution of potassium iodide (a) State the observations made(Solved)
During an experiment, chlorine gas was bubbled into a solution of potassium iodide
a) State the observations made
b) Using an ionic equation, explain why the reaction is redox.
Date posted: February 10, 2017. Answers (1)
- Hydrogen chloride gas can be prepared by reacting sodium chloride with an acid, write an equation for the reaction between sodium chloride and acid(Solved)
Hydrogen chloride gas can be prepared by reacting sodium chloride with an acid.
a) Write an equation for the reaction between sodium chloride and acid
b) Give two chemical properties of hydrogen chloride gas
c) State two use of hydrogen chloride
Date posted: February 10, 2017. Answers (1)
- State and explain what would happen if a dry red litmus paper was dropped in a gas jar dry chlorine(Solved)
State and explain what would happen if a dry red litmus paper was dropped in a gas jar dry chlorine.
Date posted: February 10, 2017. Answers (1)
- By using only dilute hydrochloric acid, describe how a student would distinguish between barium sulphite from barium sulphate(Solved)
By using only dilute hydrochloric acid, describe how a student would distinguish between barium sulphite from barium sulphate
Date posted: February 10, 2017. Answers (1)
- State and explain what would happen if a dry litmus paper was dropped in a gas jar of chlorine(Solved)
State and explain what would happen if a dry litmus paper was dropped in a gas jar of chlorine
Date posted: February 10, 2017. Answers (1)
- Give two uses of sodium hypochlorite(Solved)
Give two uses of sodium hypochlorite
Date posted: February 10, 2017. Answers (1)
- Give the conditions under which sodium hydroxide reacts with chlorine to form sodium hypochlorite(Solved)
Name the conditions under which sodium hydroxide reacts with chlorine to form sodium hypochlorite.
Date posted: February 10, 2017. Answers (1)
- During a class experiment, chlorine gas was bubbled into a solution of potassium iodide(Solved)
During a class experiment, chlorine gas was bubbled into a solution of potassium iodide
a) State the observations made.
b) Give two uses of hydrochloric acid
Date posted: February 10, 2017. Answers (1)