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- Add distilled water to ZnCl2 solid and shake until all solid dissolves
- Add NaHCO3(aq)or Na2CO3 solution to form white precipitate of ZnCO3(g)
- Filter and wash residue with a lot of water
- Dry it between two filter papers.
sharon kalunda answered the question on March 29, 2019 at 10:27
- Briefly explain an industrial application of the following processes.(Solved)
Briefly explain an industrial application of the following processes.
a) Crystallization.
(b) Fractional distillation.
Date posted: March 29, 2019. Answers (1)
- The diagrams below represent a list of apparatus which are commonly used in a chemistry laboratory:-(Solved)
The diagrams below represent a list of apparatus which are commonly used in a chemistry laboratory:-
(a) Give the correct order of the apparatus, using the letters only, show the correct arrangement that can be used to prepare and investigate the nature of PH of a sample of onion solution.
(b) Name one chemical substance and apparatus that is needed in the experiment.
Date posted: March 29, 2019. Answers (1)
- Use the information in the table below to determine the relative atomic mass of copper.(Solved)
Use the information in the table below to determine the relative atomic mass of copper.
Date posted: March 29, 2019. Answers (1)
- Draw structural formulae of two positional isomers with molecular formula C4H8.(Solved)
Draw structural formulae of two positional isomers with molecular formula C4H8.
Date posted: March 29, 2019. Answers (1)
- Use the equation below to answer the questions that follow.(Solved)
Use the equation below to answer the questions that follow.
Using oxidation numbers show where reduction has taken place.
Date posted: March 29, 2019. Answers (1)
- The curve shown below was obtained when solid naphthalene was heated to boiling.(Solved)
The curve shown below was obtained when solid naphthalene was heated to boiling.
(a) Explain in molecular terms the changes occurring in portions.
(i) AB.
(ii) DE.
(b) What is the significance of portion BC?
Date posted: March 29, 2019. Answers (1)
- 3.22g of hydrated sodium sulphate, Na2SO4.XH2O were heated to a constant mass of 1.42g. Determine the value of X in the formula. (Na = 23.0,...(Solved)
3.22g of hydrated sodium sulphate, Na2SO4.XH2O were heated to a constant mass of 1.42g. Determine the value of X in the formula. (Na = 23.0, S = 32.0, O = 16.0, H = 1).
Date posted: March 29, 2019. Answers (1)
- The figure below shows a set-up used in electrolysis of lead iodide.(Solved)
The figure below shows a set-up used in electrolysis of lead iodide.
(a) Why is heating necessary?
(b) Write the equation of the reaction that occurs at the cathode.
(c) At which electrode does reduction occurs.
Date posted: March 29, 2019. Answers (1)
- Solid J reacts with cold water but solid K does not. L reduces the oxide of M but does not reduce the oxide of K....(Solved)
Solid J reacts with cold water but solid K does not. L reduces the oxide of M but does not reduce the oxide of K. Arrange the elements in order of reactivity starting with the most reactive.
Date posted: March 29, 2019. Answers (1)
- In terms of structure and bonding explain why the component Cl2O has a very low melting and boiling point.(Solved)
In terms of structure and bonding explain why the component Cl2O has a very low melting and boiling point.
Date posted: March 29, 2019. Answers (1)
- Draw a dot (.)/cross (X) diagram to show bonding in Cl2O. (Cl = 17, O = 8).(Solved)
Draw a dot (.)/cross (X) diagram to show bonding in Cl2O. (Cl = 17, O = 8).
Date posted: March 29, 2019. Answers (1)
- The following chromatogram was obtained in an experiment to investigate the components present in certain dyes.(Solved)
The following chromatogram was obtained in an experiment to investigate the components present in certain dyes.
(a) Which two dyes when mixed would produce A?
(b) Which dye is pure?
(c) Indicate on the diagram the solvent front.
Date posted: March 29, 2019. Answers (1)
- 1.26g of lead powder were dissolved in excess nitric (VI) acid to form lead nitrate solution. All the lead nitrate solution was reacted with sodium...(Solved)
1.26g of lead powder were dissolved in excess nitric (VI) acid to form lead nitrate solution. All the lead nitrate solution was reacted with sodium sulphate solution.
(a) Write an ionic equation for the reaction between lead nitrate and sodium sulphate solutions.
(b) Determine the mass of lead salt formed in (a) above (Pb = 207, S = 32, O = 16).
Date posted: March 29, 2019. Answers (1)
- A dry cell is constructed using the following substances. Zinc metal, graphite rod, ammonium chloride paste and manganese (IV) oxide mixed with carbon powder.
(a) State...(Solved)
A dry cell is constructed using the following substances. Zinc metal, graphite rod, ammonium chloride paste and manganese (IV) oxide mixed with carbon powder.
(a) State the roles of:
(i) Ammonium chloride paste.
(ii) Manganese (IV) oxide mixed with carbon powder.
(b) Given that:
Calculate the e m f of the cell given zinc forms the negative electrode.
Date posted: March 29, 2019. Answers (1)
- Dry hydrogen chloride gas was passed over heated iron wool as shown below.(Solved)
Dry hydrogen chloride gas was passed over heated iron wool as shown below.
(a) State the observation made in the combustion tube at the end of the experiment.
(b) Write the equation for the reaction taking place:-
(i) In the combustion tube.
(ii) Leading to production of the blue flame.
Date posted: March 29, 2019. Answers (1)
- A mass of 40g of a saturated solution of potassium chlorate at 250C yields 14g of potassium chlorate when evaporated to dryness. Calculate the solubility...(Solved)
A mass of 40g of a saturated solution of potassium chlorate at 250C yields 14g of potassium chlorate when evaporated to dryness. Calculate the solubility of potassium chloride at 250C.
Date posted: March 29, 2019. Answers (1)
- The diagram below is a set-up of apparatus used to react ammonia gas with iron (IV) chloride solution.(Solved)
The diagram below is a set-up of apparatus used to react ammonia gas with iron (IV) chloride solution.
(a) State the observation made in the beaker after a few minutes.
(b) Explain why the funnel is used to deliver the ammonia into the solution.
Date posted: March 29, 2019. Answers (1)
- Give one use of radioactive isotopes in industries.(Solved)
Give one use of radioactive isotopes in industries.
Date posted: March 29, 2019. Answers (1)
- 384g of radioactive element was reduced to 48g in 540 days. Determine the half-life of X.(Solved)
384g of radioactive element was reduced to 48g in 540 days. Determine the half-life of X.
Date posted: March 29, 2019. Answers (1)
- Study the table below and use it to answer the questions that follow.(Solved)
Study the table below and use it to answer the questions that follow.
(i) In which of the solution will phenolphthalein indicator be colourless.
(ii) Which of the solutions could be used to relieve heartburn? Explain.
Date posted: March 29, 2019. Answers (1)