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- The standard electrode potentials for certain half cell reactions are shown below.(Solved)
The standard electrode potentials for certain half cell reactions are shown below.
(a) (i) Identify the strongest oxidizing agent.
(ii) Write the cell equation for a cell formed by connecting W and X cells.
(iii) Calculate the e.m.f of cell in a(ii) above.
(b) During electrolysis of silver nitrate, a current of 0.5A was passed through the electrolyte for 3 hours.
(i) Write the equation for the reaction which took place at the anode.
(ii) Calculate the mass of silver deposited. (Ag = 108, IF = 96500C)
(iii) Give two reasons why it is necessary to electroplate iron with silver.
Date posted: September 17, 2019. Answers (1)
- A sample of air contains nitrogen, oxygen and argon. Describe how oxygen gas can be obtained.(Solved)
A sample of air contains nitrogen, oxygen and argon. Describe how oxygen gas can be obtained.
Date posted: September 17, 2019. Answers (1)
- 100cm3 of0.05M Sulphuric (VI) acid were placed in the flask and small quantity of potassium Carbonate added. The mixture was boiled to expel all carbon...(Solved)
100cm3 of0.05M Sulphuric (VI) acid were placed in the flask and small quantity of potassium Carbonate added. The mixture was boiled to expel all carbon (IV) oxide. 25cm3 of the resulting solution required 18cm3 of 0.1M potassium hydroxide solution to neutralize it. Calculate the mass of potassium carbonate added. (K = 39, O = 16, C = 12)
Date posted: September 17, 2019. Answers (1)
- 12.3.0g of an organic compound containing Carbon, hydrogen and oxygen only produced 4.4g of Carbon (IV) oxide and 1.8g of water on complete combustion.
a) Calculate...(Solved)
12.3.0g of an organic compound containing Carbon, hydrogen and oxygen only produced 4.4g of Carbon (IV) oxide and 1.8g of water on complete combustion.
a) Calculate its empirical formula.
b) Calculate in molecular formula if its formula mass is 60.
Date posted: September 17, 2019. Answers (1)
- The products formed by action of heat on nitrates of element X, Y and Z are shown below.(Solved)
The products formed by action of heat on nitrates of element X, Y and Z are shown below.
a) Arrange the metals in order of increasing reactivity.
b) Which element forms a soluble carbonate?
c) Give an element that can be Y.
Date posted: September 17, 2019. Answers (1)
- a) Draw a diagram to show how an iron ring can be electroplated with pure silver.
b)Give two reasons why electroplating is necessary.(Solved)
a) Draw a diagram to show how an iron ring can be electroplated with pure silver.
b)Give two reasons why electroplating is necessary.
Date posted: September 17, 2019. Answers (1)
- Consider the flow chart below; use it to answer the questions that follow.(Solved)
Consider the flow chart below; use it to answer the questions that follow.
(i) State the most likely identity of solid F.
(ii) Write the chemical equation for the reaction between solid F and concentrated nitric (v) acid.
(iii) Name
Solution N
Solution H
(iv) Write the formula of solution N.
Date posted: September 17, 2019. Answers (1)
- Propane is a hydrocarbon. What does the term hydrocarbon mean?(Solved)
Propane is a hydrocarbon. What does the term hydrocarbon mean?
Date posted: September 17, 2019. Answers (1)
- Name the class to which the following cleansing agents belong.(Solved)
a)Name the class to which the following cleansing agents belong.
b) Which cleaning agent between (i) or (ii) above is preferred for cleaning garments while using water from a dam containing dissolved calcium chloride? Explain
Date posted: September 17, 2019. Answers (1)
- Describe how a solid mixture of Zinc sulphate and lead (ii) Sulphate can be separated into Solid samples.(Solved)
Describe how a solid mixture of Zinc sulphate and lead (ii) Sulphate can be separated into Solid samples.
Date posted: September 17, 2019. Answers (1)
- Hydrogen Chloride gas is a colourless gas which dissolves readily in water forming hydrochloric acid.
(Solved)
(i) At room temperature and pressure, 1.00dm3 of water dissolves 432 dm3 of hydrogen chloride gas. How many moles of hydrogen chloride dissolves in 1dm3 water (1 mole at r.t.p. occupies 24.0dm3)
(ii) The hydrochloric acid formed has a volume of 1.40 dm3; calculate the concentration of the acid in mol/dm3.
Date posted: September 17, 2019. Answers (1)
- The pH values of some solutions labeled K,H,L,P and R are given in the table below. Use the information to answer the questions that follow.(Solved)
The pH values of some solutions labeled K,H,L,P and R are given in the table below. Use the information to answer the questions that follow.
(a)Identify the solution with the highest concentration of hydroxyl ions.
(b)Which solution is likely to be sodium chloride solution?
(c)Which solution would react most vigorously with magnesium metal?
Date posted: September 17, 2019. Answers (1)
- Use the diagram below to answer the questions that follow:(Solved)
Use the diagram below to answer the questions that follow:
a) Identify the radiations
A
C
b)The table below gives the rate of decay for a sample of radioactive element K. Study it and answer the question that follows:
Determine the half-life of element K.
Date posted: September 17, 2019. Answers (1)
- Other than cost and ability to conduct, give two other reasons why aluminum is used for making overhead electric cables while magnesium is not.(Solved)
Other than cost and ability to conduct, give two other reasons why aluminum is used for making overhead electric cables while magnesium is not.
Date posted: September 17, 2019. Answers (1)
- If 100cm3 of 0.05M hydrogen peroxide were used to produce gas M. calculate the volume of gas M produced if the hydrogen peroxide decomposed completely.(Solved)
If 100cm3 of 0.05M hydrogen peroxide were used to produce gas M. calculate the volume of gas M produced if the hydrogen peroxide decomposed completely.
Date posted: September 17, 2019. Answers (1)
- A student set up the apparatus as shown in the diagram below to prepare and collect dry ammonia gas.(Solved)
A student set up the apparatus as shown in the diagram below to prepare and collect dry ammonia gas.
(i) Identify one mistake in the set-up and give a reason.
(ii) Name a suitable drying agent for ammonia.
(iii) Write an operation for the reaction that occurred when a mixture of ammonium chloride and calcium hydroxide was heated.
(iv) Describe one chemical test for ammonia gas.
Date posted: September 17, 2019. Answers (1)
- Study the reaction scheme below and answer the questions that follow.(Solved)
Study the reaction scheme below and answer the questions that follow.
a) Name; Gas M
Precipitate w
b) Write an equation for the formation of ;
The white solid
Colorless solution X
c) What name is given to the process that produce precipitate W
d) State two commercial uses of gas M
Date posted: September 17, 2019. Answers (1)
- Below is a simplified diagram of the Downs cell in which sodium metal is manufactured.(Solved)
Below is a simplified diagram of the Downs cell in which sodium metal is manufactured.
(i) Identify electrolyte X and gas Y.
(ii)Give two properties of sodium that make it possible to collect as shown above.
(iii) Why is graphite preferred to steel as the anode?
(iv) Explain how sodium hydroxide pellets would be obtained from sodium amalgam?
Date posted: September 17, 2019. Answers (1)
- The grid below represents part of the periodic table. Study it and answer the questions that follow.
The letters do not represent the actual symbols of...(Solved)
The grid below represents part of the periodic table. Study it and answer the questions that follow.
The letters do not represent the actual symbols of the elements.
(i) Which element will require the least amount of energy to remove one of its outermost electrons, explain.
(ii) Select the most reactive non-metal
(iii) What name is given to the family of elements to which T belong?
(iv) Between S and R, which element has a smaller atomic radius, explain.
(v) Which of the elements have a tendency of forming covalent bonds? Explain.
(vi) Write the formula of the compound formed when U reacts with T, state the type of body formed.
Formula
Bond
Date posted: September 17, 2019. Answers (1)
- The scheme below shows various reactions and process for some organic compounds.
Study it and answer the questions that follow.(Solved)
The scheme below shows various reactions and process for some organic compounds.
Study it and answer the questions that follow.
i. Name process I and name any other product formed in the process.
Process
Product
ii) Name the reagent and condition required in process II.
Reagent
Condition
iii) Name the catalyst and reagent required in step IV.
Catalyst
Reagent
iv) Give any one use of the product formed in process (V)
v) Name process (VI)
Date posted: September 17, 2019. Answers (1)