Distinguish between the terms deliquescent and efflorescent as used in chemistry
ANSWERS
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Sodium hydroxide can be prepared by the following methods; I and II.
(a) Name the precaution that needs to be taken in method I.
(b) Give the name of process A. (c) Give one use of sodium hydroxide,
ANSWERS
(a) Small piece of sodium metal (pea size) with a lot of water.
Perform the experiment wearing goggles. (b) Electrolysis. (c) Manufacture of soap.
Exhaust fumes of some cars contain carbon(II)oxide and other gases.
(a) Explain how carbon (II) oxide is formed in the internal combustion engines. (b) Name two gases other than carbon (II) oxide that are contained in exhaust fumes and are pollutants.
ANSWERS
(a) Carbon (II) oxide is formed in the internal combustion engines when fuel burns under limited oxygen.
(b) Pollutant gas - Carbon (IV) oxide, Nitrogen (1V) oxide and Sulphur (IV) oxide.
During a class experiment, chlorine gas was bubbled into a solution of potassium iodide.
(a) State the observations made. (b) Using an ionic equation, explain why the reaction is redox .
State two reasons why hydrogen is not commonly used as a fuel.
ANSWERS
(a) What is meant by a strong acid?
(b) In an experiment 40cm3 of 0.5M hydrochloric acid was reacted with excess sodium carbonate and the volume of carbon (IV) oxide produced recorded with time. In another experiment, the same volume and concentration of ethanoic acid was also reacted with excess sodium carbonate and the volume of carbon (IV) oxide produced recorded with time. On the grid below, sketch and label the curves if the volumes of carbon (IV) oxide were plotted against time.
When lead(II) nitrate is heated, one of the products is a brown gas.
(a) Write the equation of the reaction that occurs . (b) If 0.290dm3 of the brown gas was produced, calculate the mass of the lead(II) nitrate that was heated. (R .F.M of lead (II) nitrate = 331; Molar gas volume = 24dm3 ).
A certain mass of gas occupies 0.15dm3 at 293K and 98,648.5Pa. Calculate its Volume at 101,325Pa and 273K.
The diagram below represents part of the periodic table. Use it to answer the questions that follow.
a) Write the electronic arrangement for the stable ion formed by W.
(b) Write an equation for the reaction between V and Q. (c) How do the ionization energies of the elements M and T compare? Explain.
The set up below shows how nitrogen gas is prepared in a laboratory.
(a) Describe how nitrogen gas us formed in the flask.
(b). Nitrogen is inert, state one use of the gas based on this property.
ANSWERS
(a) Oxygen is used up
(b) Lighting of bulbs
A mixture contains ammonium chloride, copper (II) oxide and sodium chloride.
Describe how each o the substances can be obtained from the mixture.
ANSWERS
Heat the mixture to sublime the ammonium chloride.
Add water to dissolve the sodium chloride ; copper (ii) oxide does not dissolve Filter and evaporate the filtrate to obtain sodium chloride.
Complete the nuclear equation below:
(c) Give one harmful effect of radioisotopes.
(a) What name is given to the process by which alcohol is formed from a carbohydrate?
(b) Explain why the solubility of ethane in water is lower than that of ethanol.
ANSWERS
(a) Fermentation.
(b) Ethane remains in molecular form while ethanol forms hydrogen bonds with water. |
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