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Sodium carbonate provides carbonate ions which combine with calcium/magnesium ions that cause hardness to form precipitates of calcium carbonate or magnesium carbonate, respectively.
johnmulu answered the question on February 15, 2017 at 06:02
- Dissolving of potassium nitrate in water is an endothermic process. Explain the effect of increase in temperature on the solubility of potassium nitrate(Solved)
Dissolving of potassium nitrate in water is an endothermic process. Explain the effect of increase in temperature on the solubility of potassium nitrate.
Date posted: February 15, 2017. Answers (1)
- Starting with zinc sulphate solution, describe how a sample of zinc oxide can be obtained(Solved)
Starting with zinc sulphate solution, describe how a sample of zinc oxide can be obtained.
Date posted: February 15, 2017. Answers (1)
- Aqueous hydrogen chloride reacts with potassium manganate (VII) to produce chlorine gas, while a solution of hydrogen chloride in methylbenzene has no effect on potassium manganate (VII)(Solved)
Aqueous hydrogen chloride reacts with potassium manganate (VII) to produce chlorine gas, while a solution of hydrogen chloride in methylbenzene has no effect on potassium manganate (VII). Explain this observation.
Date posted: February 15, 2017. Answers (1)
- (a) Name two cations that are present in hard water (b) Explain how the ion exchange resin softens hard water(Solved)
a) Name two cations that are present in hard water.
b) Explain how the ion exchange resin softens hard water.
Date posted: February 15, 2017. Answers (1)
- Describe how the presence of zinc ions and sulphate ions can be established(Solved)
A sample of river water is suspected to contain zinc and sulphate ions. Describe how the presence of zinc ions and sulphate ions can be established.
Date posted: February 15, 2017. Answers (1)
- Soap dissolves in water dissolves in water according to the equation below; NaSt(aq) $\rightarrow$ Na+(aq) + St- where St- is the stearate ion(Solved)
Soap dissolves in water dissolves in water according to the equation below; NaSt(aq) $\rightarrow$ Na+(aq) + St- where St- is the stearate ion.
a) Write the formula of the scum formed when soap is used in hard water.
b) Write the ionic equation for the reaction that occurs when sodium carbonate is used to remove hardness in water
Date posted: February 13, 2017. Answers (1)
- A sample of fertilizer is suspected to be calcium ammonium nitrate. Describe chemical test for each of the following ions in the sample(Solved)
A sample of fertilizer is suspected to be calcium ammonium nitrate. Describe chemical test for each of the following ions in the sample:
a) Calcium ions
b) Ammonium ions.
Date posted: February 13, 2017. Answers (1)
- For each of the following reactions, state the observation and write the formula of the compound responsible for the observation(Solved)
For each of the following reactions, state the observation and write the formula of the compound responsible for the observation:
a) Bromine water is added to aqueous potassium iodide
b) Excess aqueous ammonia is added to copper (II) hydroxide.
Date posted: February 13, 2017. Answers (1)
- Hardness of water may be removed by either boiling or addition of chemicals(Solved)
Hardness of water may be removed by either boiling or addition of chemicals.
a) Write an equation to show how boiling removes hardness of water.
b) Name two chemicals that are used to remove hardness of water.
Date posted: February 13, 2017. Answers (1)
- The elements nitrogen, phosphorous and potassium are essential for plant growth(Solved)
The elements nitrogen, phosphorous and potassium are essential for plant growth.
Potassium in fertilizers may be in the form of potassium nitrate.
Describe how a sample of a fertilizer may be tested to find out if it contained nitrate ions.
Date posted: February 13, 2017. Answers (1)
- Name two methods that can be used to remove permanent hardness from water(Solved)
Name two methods that can be used to remove permanent hardness from water.
Date posted: February 13, 2017. Answers (1)
- Explain why permanent hardness in water cannot be removed by boiling(Solved)
Explain why permanent hardness in water cannot be removed by boiling.
Date posted: February 13, 2017. Answers (1)
- Starting from solid magnesium oxide, describe how a solid sample of magnesium hydroxide can be prepared(Solved)
a) Starting from solid magnesium oxide, describe how a solid sample of magnesium hydroxide can be prepared.
b) Give one use of magnesium hydroxide.
Date posted: February 13, 2017. Answers (1)
- Water from a town in Kenya is suspected to contain chloride ions but not sulphate ions. Describe how the presence of the chloride ions in water can be shown(Solved)
Water from a town in Kenya is suspected to contain chloride ions but not sulphate ions. Describe how the presence of the chloride ions in water can be shown.
Date posted: February 13, 2017. Answers (1)
- Zinc oxide reacts with acids and alkalis (a) Write the equation for the reaction between zinc oxide and...(Solved)
Zinc oxide reacts with acids and alkalis
a) Write the equation for the reaction between zinc oxide and
i)Dilute sulphuric (VI) acid
ii) Sodium hydroxide solution
Date posted: February 13, 2017. Answers (1)
- Starting with aluminium sulphate, describe how solid sample of aluminium hydroxide could be prepared(Solved)
Starting with aluminium sulphate, describe how solid sample of aluminium hydroxide could be prepared.
Date posted: February 13, 2017. Answers (1)
- State the constant force that opposes the motion of a stone initially at rest, as it fails through air from a tall building(Solved)
State the constant force that opposes the motion of a stone initially at rest, as it fails through air from a tall building.
Date posted: February 11, 2017. Answers (1)
- Neutralization is one of the methods of preparing salts (i) What is meant by neutralization(Solved)
Neutralization is one of the methods of preparing salts
i) What is meant by neutralization
ii) Describe how would prepare crystals of sodium nitrate starting with 200 cm3 of 2M sodium hydroxide
iii) Write an equation for the reaction that takes place when a solid sample of sodium nitrate is heated.
Date posted: February 10, 2017. Answers (1)
- (a) State one cause of temporary hardness in water (b) How does distillation remove hardness from water?(Solved)
a) State one cause of temporary hardness in water
b) How does distillation remove hardness from water?
Date posted: February 10, 2017. Answers (1)
- 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)