|
(a) The diagram below represents a set up that was used to obtain dry nitrogen from air. Study it and answer the questions that follow
Expected Response
Related Chemistry Questions and Answers on nitrogen and its compounds form 3 level
0 Comments
The reaction between and methanoic acid at 300C proceeds according to the information given below 
(a) On the grid below, plot a graph of concentration of Bromine (Vertical axis against time) (b) From the graph determine: (i) The concentration of bromine at the end of 3 minutes (ii) The rate of reaction at time ‘t’ where t = 1 ½ minutes (c) Explain how the concentration of bromine affects the rate of reaction (d) On the same axis sketch the curve that would be obtained if the reaction was carried out at 200C and label the curve as curve II. Give a reason for your answer.
Expected Response
(a) Study the information below and answer the questions that follow:
The letters do not represent the actual symbols of the elements 
Expected Response
(a) The diagram below shows the extraction of sodium metal using the downs cell. Study it answer the questions that follow
Expected Response
(a) Give the names of the following compounds
(b) Study the information in the table below and answer the questions that follow
(i) Name the reagents used in:
Step I ……………………. Step II …………………….. Step III …………………….. (ii) Write an equation for the complete combustion of CH = CH (iii) Explain one disadvantage of the continued use of items made from the compound formed in step III
Expected Response
(i) Which element is likely to be hydrogen? Give a reason for your answer (ii) What is the Eθ value of the strongest reducing agent? (iii) In the space provided draw a labeled diagram of the electrochemical cell that would be obtained when half – cells of elements B and D are combined (iv) Calculate the Eθ value of the electrochemical cell constructed in (iii) above (b) During the electrolysis of aqueous copper (II) sulphate using copper electrodes, a current of 0.2 amperes was passed through the cell for 5 hours (i) Write an ionic equation for the reaction that took place at the anode (ii) Determine the change in mass of the anode which occurred as a result of the electrolysis process (Cu= 63.5, 1 Faraday = 96,500 coulombs).
Expected Response
Aqueous potassium sulphate was electrolysed using platinum electrodes in a cell. a) Name the products formed at the cathode and anode. Anode b) How does the concentration of the electrolyte change during electrolysis. c) Why would it not be advisable to electolyse aqueous potassium sulphate using potassium metal electrodes.
Expected Response
In an experiment to separate a mixture of two organic liquids, liquid M (b.p 560C) And liquid (b.p. 1180C), a student set up the apparatus shown below 
Expected Response
An element Y has the electronic configuration 2.8.5
Expected Response
90cm3 of 0.01M calcium hydroxide were added to a sample of water containing 0.001 moles of calcium hydrogen carbonate. a) Write an equation for the reaction which took place b) Calculate the number of moles of calcium ions in 90cm3 of 0.01M calcium hydroxide. c) What would be observed if soap solution was added drop wise to a sample of the water after the addition of calcium hydroxide? Give a reason.
Expected response
A gas occupies a volume of 400cm3 at 500k and 1 atmosphere pressure. What will be the temperature of the gas when the volume and pressure of the gas is 100cm3 and 0.5 atmospheres respectively.
Expected Response
In an equation below, identify the reagent that acts as abase. Give a reason. H2O(aq) + H2O(l) → H3O(aq) + HO2-(aq)
Expected Response
When 0.6g of element J were completely burnt in oxygen and all the heat evolved was used to heat 500cm3 of water, the temperature of the water rose from 230C to 320C. Calculate the relative atomic mass of element J given that the specific heat capacity of water = 4.2JK-1g-1, density of water = 1.0g/cm3 and molar heat is combustion of J is 380Kjmol-1
Expected Response
Potassium sulphite solution was prepared and divided into two portions. The first portion gave a white precipitate when reacted with barium nitrate. On addition of dilute hydrochloric acid the white precipitate disappeared.
a) Write the formula of the compound which formed as the white precipitate. b) Write the equation for the reaction between dilute hydrochloric acid and the compound whose formula is written in (a) above. c) What observation would be made if one drop of potassium dichromate solution was added to the second portion followed by dilute hydrochloric acid?
Expected Response
In an experiment, chlorine gas was passed into moist hydrogen sulphide contained in a boiling tube as shown in the diagram
a) What observation was made in the boiling tube?
b) Write an equation for the above reaction. c) What precaution should be taken in carrying out this experiment? Give a reason.
Expected Response
Explain why anhydrous magnesium chloride is fairly soluble in organic solvents while anhydrous magnesium chloride is insoluble.
Expected Response
Aluminum chloride is covalent while magnesium chloride is ionic
Sulphur burns in air to form sulphur dioxide. A simple energy level diagram for the reaction is given below. Study the diagram and answer the questions that follow.
a) What do the following represent?
b) Write an expression, for △H3 in terms of △H1 and △H2
Expected Response
0.63g of lead powder were dissolved in excess nitric acid to form lead nitrate solution. All the lead nitrate solution was reacted with sodium sulphate solution.
Expected Response
The empirical formula of a hydrocarbon is C2H3.The hydrocarbon has a relative molecular mass of 54..(H = 1.0, C = 12.0). a) C2H3 b) Draw the structural formula of the hydrocarbon c) To which homologous series does the hydrocarbon drawn in (b) above belong?
Expected Response
(a) In an experiment, dry hydrogen chloride gas was passed through heated zinc turnings as shown in the diagram below. The gas produced was then passed through heated lead (II) oxide.
Expected Response
Calculate the mass of nitrogen dioxide gas that would occupy the same volume as 10g of hydrogen gas at same temperature and pressure.(H = 1.0, N = 14.0, o = 16.0)
Expected Response
Using dots (.)and crosses (x) to represent outermost electrons, draw diagrams to show the bonding in CO2 and H3O+ (Atomic numbers; H = 1.0,C= 14.0, O = 8 ).
Expected Response
The information below relates to element L, Q, R and T. The letters do not represent the actual symbols of the elements. Arrange the elements in
a) Give the formula of an oxide which reacts with both dilute hydrochloric acid and hot concentrated sodium hydroxide. b) Give the formulae of the products formed when the oxide in (a) above reacts with excess hot concentrated sodium hydroxide.
Expected Response
A student set up the experiment below to collect gas K the glass wool was heated before heating the Zinc powder.
Why was it necessary to heat the moist glass wool before heating zinc powder
Expected Response
Study the scheme below and answer the questions that follow.
a) Write the formula of the caution present in solution F. b) What property of chlorine is shown in step I c) Write an equation for the reaction which occurs in step III |