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- The table below shows the effect of passing an electric current through substances using unreactive electrodes,and a bulb in the circuit.(Solved)
The table below shows the effect of passing an electric current through substances using unreactive electrodes,and a bulb in the circuit.
a)Identify the experiments in which the bulb did not light.
(b)Explain your answer in (a) above.
Date posted: March 19, 2019. Answers (1)
- Moist hydrogen sulphide gas was passed through a tube containing wet sulphur (IV) oxide gas as shown below.(Solved)
Moist hydrogen sulphide gas was passed through a tube containing wet sulphur (IV) oxide gas as shown below.
(a) State the observation (s) made.
(b) Write an equation for the reaction above.
(c) Giving a reason, which substance undergoes reduction above.
Date posted: March 19, 2019. Answers (1)
- Give two differences between chemical reactions and nuclear reactions.(Solved)
Give two differences between chemical reactions and nuclear reactions.
Date posted: March 19, 2019. Answers (1)
- 0.585g of sodium chloride were dissolved in 50cm³ of de-ionised water. The temperature of the water dropped from 29°C to 17°C. Find the molar heat...(Solved)
0.585g of sodium chloride were dissolved in 50cm³ of de-ionised water. The temperature of the water dropped from 29°C to 17°C. Find the molar heat of solution of sodium chloride. Specific heat capacity of solution 4.2 kJk-2Kg-1, density of solution is 1g/cm³. (Na - 23.0, Cl = 35.5)
Date posted: March 19, 2019. Answers (1)
- Study the chart below and answer the question that follow:(Solved)
Study the chart below and answer the question that follow:
(a) Identify
(i) the metal ions in solution K.
(ii) the white precipitate L.
(b) What property of the white precipitate L is illustrated by steps I and II
Date posted: March 19, 2019. Answers (1)
- Study the set-up below and answer the questions that follow.
(Solved)
Study the set-up below and answer the questions that follow.
(a) Write an equation for the reaction that took place.
(b) What observations is made in the combustion tube.
(c) Name another gas which could be used in place of carbon (II) oxide.
Date posted: March 19, 2019. Answers (1)
- The boiling points of some compounds of hydrogen with some elements in group 4 and 6 of the periodic table are given below.(Solved)
The boiling points of some compounds of hydrogen with some elements in group 4 and 6 of the periodic table are given below.
a) Which of the compounds CH4 and SiH4 has the stronger inter molecular forces?Explain.
(b) Explain why the boiling points of H2O and H2S show different trends from that of CH4 and SiH4.
Date posted: March 19, 2019. Answers (1)
- Sulphur is a component in fuels. Explain the effects of continued use of sulphur containing fuels on the
environment.(Solved)
Sulphur is a component in fuels. Explain the effects of continued use of sulphur containing fuels on the
environment.
Date posted: March 19, 2019. Answers (1)
- The table below shows the number of valence electrons of elements X, Y and Z.(Solved)
The table below shows the number of valence electrons of elements X, Y and Z.
(a) Explain why X and Z would not be expected to form a compound.
(b) Write an equation to show the effect of heat on the carbonate of Z.
(c) Write the formula for the most stable ion of element Y.
Date posted: March 19, 2019. Answers (1)
- a)Study the flow chart below and answer questions that follow.(Solved)
a)Study the flow chart below and answer questions that follow.
Name substances. W,Y
(b) An organic compound K reacted with bromine to produce 2, 3 - dibromobytane .
(i) Name the compound K.
(ii) Draw the structural formular of compound K.
Date posted: March 19, 2019. Answers (1)
- In terms of structure and bonding explain why silicon (IV) oxide is a solid while sulphur (IV) oxide is a gas at room temperature.(Solved)
In terms of structure and bonding explain why silicon (IV) oxide is a solid while sulphur (IV) oxide is a gas at room temperature.
Date posted: March 19, 2019. Answers (1)
- A cell is represented as Zn(S) / Zn2+(aq) // Cu2+(aq) / Cu(S) write down
(i) The oxidation half equation.
(ii) The reduction half equation.
(iii) The...(Solved)
A cell is represented as Zn(S) / Zn2+(aq) // Cu2+(aq) / Cu(S) write down
(i) The oxidation half equation.
(ii) The reduction half equation.
(iii) The overall cell equation.
Date posted: March 19, 2019. Answers (1)
- The data given below was recorded when metal M was completely burnt in air. M is not the actual symbol of the metal. (RAM M...(Solved)
The data given below was recorded when metal M was completely burnt in air. M is not the actual symbol of the metal. (RAM M = 56.0, O=16)
Mass of empty crucible and lid = 5.240g
Mass of crucible, lid and metal m = 5.352g
Mass of crucible, lid, metal oxide = 5.400g
(a) Determine the mass of
(i) Metal m
(ii) Oxygen.
(b) Determine the empirical formula of the meat oxide.
Date posted: March 19, 2019. Answers (1)
- Study the flow chart below and answer the question that follow.(Solved)
Study the flow chart below and answer the question that follow.
(i) Name the following substance
Gas W
Solid Y
ii) Write an equation for the formation of the brown precipitate .
Date posted: March 19, 2019. Answers (1)
- Solutions may be classified as strongly basic, weakly basic neutral weakly acidic, strongly acidic. The
information below gives solution and their pH values. Study it and...(Solved)
Solutions may be classified as strongly basic, weakly basic neutral weakly acidic, strongly acidic. The
information below gives solution and their pH values. Study it and answer the questions that follow.
Classify the solution in the table above using the stated classification B, C & D
Date posted: March 19, 2019. Answers (1)
- A radioactive isotope decays to 50 grammes in 100 days. The half-life of the isotope is 25 days. Calculate the initial mass of the isotope.(Solved)
A radioactive isotope decays to 50 grammes in 100 days. The half-life of the isotope is 25 days. Calculate the initial mass of the isotope.
Date posted: March 19, 2019. Answers (1)
- Draw and name two isomers of compound C4H9Br.(Solved)
Draw and name two isomers of compound C4H9Br.
Date posted: March 19, 2019. Answers (1)
- (i) State the Charles' Law. (1 mark)
(ii) A given mass of a gas had a volume of 40cm³ at 20°C and 625mm Hg of pressure....(Solved)
(i) State the Charles' Law.
(ii) A given mass of a gas had a volume of 40cm³ at 20°C and 625mm Hg of pressure. Find the
temperature at which the volume of the gas would be 60cm³ at a pressure of 625mmHg.
Date posted: March 19, 2019. Answers (1)
- (a) State and explain the observations made when a few drops of concentrated sulphuric (VI) acid were
added to glucose in a beaker.
(b) State two...(Solved)
(a) State and explain the observations made when a few drops of concentrated sulphuric (VI) acid were
added to glucose in a beaker.
(b) State two uses of sulphuric (VI) acid.
Date posted: March 19, 2019. Answers (1)
- In an experiment air was passed through several reagents as shown in the flow chart below.(Solved)
In an experiment air was passed through several reagents as shown in the flow chart below.
(a) Write an equation for the reaction which takes place in the chamber with magnesium powder.
(b) State the Role of concentrated potassium hydroxide solution.
(c) What observation is made in the chamber containing copper turnings.
Date posted: March 19, 2019. Answers (1)