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- When a compound X was heated, a brown gas and a black residue were produced. Give the formula of:
(i) The brown gas.
(ii) The black...(Solved)
When a compound X was heated, a brown gas and a black residue were produced. Give the formula of:
(i) The brown gas.
(ii) The black residue.
Date posted: March 29, 2019. Answers (1)
- 0.92g of ethanol were found to burn in excess air producing a temperature rise of 32.5oC in 200cm3 of water(C=12.0,H=1.0,O=16.0) Density of water is 1g/cm3,...(Solved)
0.92g of ethanol were found to burn in excess air producing a temperature rise of 32.5oC in 200cm3 of water(C=12.0,H=1.0,O=16.0) Density of water is 1g/cm3, specific heat capacity of water is 4.2KjKg-1K-1.
(a) Write the equation for the combustion of ethanol.
(b) Determine the molar heat of combustion of ethanol
Date posted: March 29, 2019. Answers (1)
- The structure of synthetic rubber is shown below;(Solved)
The structure of synthetic rubber is shown below;
a) Determine the relative molecular mass of a polymer made of 250 monomers.
(c=12,H=1 and Cl=35.5)
b) Give one advantage of natural polymers over synthetic ones.
Date posted: March 29, 2019. Answers (1)
- The diagram below shows electrolysis of dilute copper (II) sulphate solution using copper electrodes;(Solved)
The diagram below shows electrolysis of dilute copper (II) sulphate solution using copper electrodes;
a) State the observations made at electrode A and B
b) Write the equation of reaction at electrode A
Date posted: March 29, 2019. Answers (1)
- Below is a simplified process for manufacture of sodium carbonate by Solvay process.
a) Name substance M.
b) Name the process taking place in step II.
c)...(Solved)
Below is a simplified process for manufacture of sodium carbonate by Solvay process.
a) Name substance M.
b) Name the process taking place in step II.
c) Write an equation for the reaction in step III.
d) What is the fate of ammonium chloride in the solvay process.
Date posted: March 29, 2019. Answers (1)
- State and explain the trend in the boiling points of group (VII) elements down the group.(Solved)
State and explain the trend in the boiling points of group (VII) elements down the group.
Date posted: March 29, 2019. Answers (1)
- Study the reaction below and answer the questions that follow.(Solved)
Study the reaction below and answer the questions that follow.
a) State and explain the observation made when a mixture at equilibrium is heated.
b) If pressure is exerted at the mixture at equilibrium, what observation will be made?
Date posted: March 29, 2019. Answers (1)
- In reference to carbon (IV) oxide, distinguish between covalent bonds and Van der Waals forces.(Solved)
In reference to carbon (IV) oxide, distinguish between covalent bonds and Van der Waals forces.
Date posted: March 29, 2019. Answers (1)
- Using dots (.) and crosses (x) to represent electrons, show the bonding in hydroxonium ion (H=1 O=8).(Solved)
Using dots (.) and crosses (x) to represent electrons, show the bonding in hydroxonium ion (H=1 O=8).
Date posted: March 29, 2019. Answers (1)
- Explain why water molecule is capable of reacting with hydrogen ion (H+) to form hydroxonium ion (H3O+).(Solved)
Explain why water molecule is capable of reacting with hydrogen ion (H+) to form hydroxonium ion (H3O+).
Date posted: March 29, 2019. Answers (1)
- Study the diagram below and answer the questions that follow(Solved)
Study the diagram below and answer the questions that follow
a) Name particles A and B
b) What property of B makes it not to be deflected by magnetic/electric field
Date posted: March 28, 2019. Answers (1)
- Compare the atomic sizes of sodium and magnesium. Explain.(Solved)
Compare the atomic sizes of sodium and magnesium. Explain.
Date posted: March 28, 2019. Answers (1)
- In an experiment, two pieces of iron sheets were wrapped in each case with zinc and copper metal sheets as shown below.They were left in...(Solved)
In an experiment, two pieces of iron sheets were wrapped in each case with zinc and copper metal sheets as shown below.They were left in the open for some months.
State and explain the observations made in the experiments; (I), (II)
Date posted: March 28, 2019. Answers (1)
- Name the chief ore of iron and write its formula(Solved)
Name the chief ore of iron and write its formula
Date posted: March 28, 2019. Answers (1)
- Name the following processes;
a) When anhydrous calcium chloride is left in an open beaker overnight a solution was formed.
b) When sodium carbonate decahydrate crystals...(Solved)
Name the following processes;
a) When anhydrous calcium chloride is left in an open beaker overnight a solution was formed.
b) When sodium carbonate decahydrate crystals are left in an open beaker for some days it turned into a powder.
Date posted: March 28, 2019. Answers (1)
- Name the following organic compounds.(Solved)
Name the following organic compounds.
Date posted: March 28, 2019. Answers (1)
- The diagram below represents a method of separation used to separate two liquids A and B. use it to answer the questions that follow(Solved)
The diagram below represents a method of separation used to separate two liquids A and B. use it to answer the questions that follow
a) Name two properties that makes it possible for the two liquids to be separated.
b) Give one alternative method that may be used to separate the two liquids.
Date posted: March 28, 2019. Answers (1)
- 60cm³ of oxygen gas diffused through a porous hole in 50 seconds. How long will it take 80cm³ of sulphur (IV) oxide to diffuse through...(Solved)
60cm³ of oxygen gas diffused through a porous hole in 50 seconds. How long will it take 80cm³ of sulphur (IV) oxide to diffuse through the same hole under the same conditions (S = 32, O = 16).
Date posted: March 28, 2019. Answers (1)
- Starting with solid lead (II) carbonate, briefly describe how a sample of lead (II) chloride can be prepared.(Solved)
Starting with solid lead (II) carbonate, briefly describe how a sample of lead (II) chloride can be prepared.
Date posted: March 28, 2019. Answers (1)
- The formulae below belong to 2 cleansing agents.(Solved)
The formulae below belong to 2 cleansing agents.
(a) Which of the two cleaning agents would lather readily with hard water?
(b) State one disadvantage of the continued use of cleansing agent II.
(c) Write the formula of the compound formed when cleansing agent I is used with water containing Mg2+ ions.
Date posted: March 28, 2019. Answers (1)