- The grid given 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 element.
- Select a letter which represents an element that loses electrons more readily
Give a reason for your answer. (2 marks) - Explain why the atomic radius of P is found to be smaller than that of N. (2 marks)
- Element M reacts with water at room temperature to produce 0.02 dm3 of gas. Determine the mass of M which was reacted with water. (Molar gas volume at room temperature is 24 dm3, Relative atomic mass of M = 7)
- Select a letter which represents an element that loses electrons more readily
- Use the information in the table below to answer the questions that follow.
(These letters are not the symbols of the elements.)
Identify a letter which represents an element in the table calcium, carbon or sulphur. Give a reason in each case.
- The grid given 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 element.
- What is meant by the term 'Enthalpy of formation'? (1 mark)
- The following enthalpies of combustion of carbon, methane and hydrogen are indicated below:
Enthalpy of combustion of CH4 = -890 kJ mol-1- Draw an energy cycle diagram that links the enthalpy of formation of methane to enthalpies of combustion of carbon, hydrogen and methane. (2 marks)
- Determine the enthalpy of formation of methane. (2 marks)
- Draw an energy cycle diagram that links the enthalpy of formation of methane to enthalpies of combustion of carbon, hydrogen and methane. (2 marks)
- What is meant by the term 'Enthalpy of formation'? (1 mark)
- An experiment was carried out where different volumes of dilute hydrochloric acid and aqueous sodium hydroxide both at 250C were mixed and stirred with a thermometer. The highest temperature reached by each mixture was recorded in the table below:
- On the grid provided, plot a graph of hoghest temperature (vertical axis), against volume of hydrochloric acid (horizontal axis). (3 marks)
- Using your graph, determine the:
- Highest temperature reached; (1/2 mark)
- Volume of acid and base reacting when the highest temperature is reached; ( 1/2 mark)
- Calculate the amount of heat liberated during the neutralisation process.
(Specific heat capacity is 4.2 g-1K-1 and the density of the solution is 1.0 g cm-3) (2 marks)
- On the grid provided, plot a graph of hoghest temperature (vertical axis), against volume of hydrochloric acid (horizontal axis). (3 marks)
- The molar neutralisation between hydrochloric acid and ammonia solution was found to be -52.2 kJ mol-1, while that of hydrochloric acid and sodium hydroxide was -57. 1 kJ mol-1. Explain the difference in these values. (2 marks)
- The diagram below shows the Frasch process used for extraction of sulphur.
Use it to answer the questions that follow.- Identify X. (1 mark)
- Why is it necessary to use super heated water in this process? (1 mark)
- State two physical properties of sulphur that makes it possible for it to be extracted by this method. (2 marks)
- The diagram below shows part of the processes of manufacture of sulphuric (VI) acid. Study it and answer the questions that follow.
- Write an equation for the formation of sulphur (IV) oxide from sulphur. (1 mark)
- What is the role of concentrated sulphuric (VI) acid in chamber A? (1 mark)
- Name two catalysts that can be used in catalystic chamber B. (2 marks)
- State two roles of heat exchanger. (2 marks)
- Explain one way in which sulphur (IV) oxide is a pollutant.
- What observations would be made when a few drops of concentrated sulphur (VI) acid are added to crystals of sugar? Explain your answer. (1 mark)
- The diagram below shows the Frasch process used for extraction of sulphur.
- The set up below can be used to produce sodium hydroxide by electrolysing brine.
- Identify the gas Y. (1 mark)
- Describe how aqueous sodium hydroxide is formed in the above set-up. (2 marks)
- One of the uses of sodium hydroxide is in the manufacturing of soaps.
State one other use of sodium hydroxide. (1 mark)
- Study the information given in the table below and answer questions that follow.
- Construct an electrochemical cell that will produce the largest emf. (3 marks)
- Calculate the emf of the cell constructed in (i) above. (2 marks)
- Why is it not advisable to store a solution containing E+ ions in acontainer made of H? (2 marks)
- The set up below can be used to produce sodium hydroxide by electrolysing brine.
- Describe one method that can be used to distinguish between sodium sulphate and sodium hydrogen sulphate. (2 marks)
- Describe how a pure sample of lead (II) sulphate can be prepared in the laboratory starting with lead metal. (3 marks)
- Study the flow chart below and answer the questions that follow.
- Write the equation for the reaction in:
- Step II (1 mark)
- Step IV (1 mark)
- State the observations made in step III. Explain. (2 marks)
- Name another substance that be used in step V. (1 mark)
- Write the equation for the reaction in:
- Describe one method that can be used to distinguish between sodium sulphate and sodium hydrogen sulphate. (2 marks)
- Distinguish between a neutron and a proton. (1 mark)
- What is meant by radioactive substance? (1 mark)
- State two dangers associated with radioactive substances in the environment. (2 marks)
- The isotopes of hydrogen , deuterium (21D) and tritium (31T) react to form element Y and neutron particles, according to the equation below:
21D + 31T -----> abY + 10n- What is the atomic:
- mass of Y; (1 mark)
- number of Y. (1 mark)
- What is tha name given to the type of reaction undergone by the isotopes of hydrogen? (1 mark)
- What is the atomic:
- What is meant by the half-life of a radioactive substance? (1 mark)
- 288g of a radioactive substance decayed to 9g in 40 days. Determine the half-life of the radioactive substance. (2 marks)
- Distinguish between a neutron and a proton. (1 mark)
- Give the systematic names for the follwing compounds:
- CH3CH2COOH; (1 mark)
- CH3CH2CH2CHCH2 (1 mark)
- CH C CH2CH3. (1 mark)
- Study the flow chart below and use it to answer the questions that follow:
- Identify the organic compound K. (1 mark)
- Write the formula of M. (1 mark)
- Give one reagent that can be used in:
- Step I; (1 mark)
- Step II. (1 mark)
- Write an equation of the reaction in step III. (1 mark)
- The structure below represents a type of a cleansing agent.
Describe how the cleansing agent removes grease from a piece of cloth. (3 marks)
- Give the systematic names for the follwing compounds: