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The set up below was used to separate a mixture of methanol and propanol. Study it and answer the question that follow.
a) State the function of X
b) Which liquid will collect first in the beaker? give a reason.
ANSWERS
Given that the atomic number of Y is 13 and that of Z is 9:
a)Write the electronic arrangement of Y and Z; b) Draw the dot (.) and cross(x) diagram for the compound formed by Y and Z
ANSWERS
In the contact process, during the production of sulphur (VI) oxide, a catalyst is used.
Give two reasons why vanadium (V) oxide is preferred to platinum.
ANSWERS
Draw a set up that can be used to separate a mixture of sand and iodine
ANSWERS
Use the part of the periodic table given below to answer the questions that follow (Letters are not the actual symbols of the elements)
a) Identify the element that forms giant covalent structures
b) Identify one element that does not form compounds c) Write the formula for the nitride of M
ANSWERS
In an experiment on rates of reaction, potassium carbonate was reacted with dilute sulphuric (Vi) acid
(a)What would be the effect of an increase in the concentration of the acid on the rate of the reaction? (b) Explain why the rate of reaction is found to increase with temperature.
ANSWERS
(a) Rate increases.
(b) Temperature increases the kinetic energy of the particles increasing the number of collisions.
A measuring cylinder fitted with moist steel wool was inverted in a trough of water as shown in the diagram below
(a)State and explain the observations made on the;
i) Moist steel wool after four days. ii) Water level in the measuring cylinder after four days. (b) What would be the effect of using steel wool moistened with salty water?
ANSWERS
(a) (i) It turned brown /blue/violet/green.
(ii) The water level rose up the gas jar/occupy space left by reacted 02 (b) The brown colour would be more since the salt accelerates rusting/rust faster.
Study the set up below and answer the questions that follow
(a)Write an equation for the reaction between ammonia and copper (II) oxide.
(b) During the experiment, the colour of the contents in the water trough changed. State the colour change observed and give an explanation.
ANSWERS
When 20cm3 of 1 M sodium hydroxide was mixed with 20cm3 of 1 M hydrochloric acid, the temperature rose by 6.70C Assuming the density of the solution is 1 g/cm3 and the specific heat capacity of the solution is 4.2Jg-1k-1.
(a) Calculate the molar heat of neutralization; (b) When the experiment was repeated with 1 M ethanoic acid, the temperature changes was found to be lower than that with 1 M hydrochloric acid. Explain.
ANSWERS
(b)Some energy is used to ionise the weak acid first before it can neutralize. So not all energy is used in neutralization.
100cm3 of 0.005 M sulphuric (VI) acid were placed in a flask and a small quantity of anhydrous sodium carbonate added. The mixture was boiled to expel all the carbon (IV) oxide. 25cm3 of the resulting solution required 18cm3 of 0.1 M sodium hydroxide solution to neutralize it.
Calculate the mass of sodium carbonate added. (Na = 23.0; O=16.0; C=12.0)
ANSWERS
Study the flow chart below and answer the questions t hat follow.
Identify Z and M.
Z……………………… M……………………
ANSWERS
One of the ores of copper has formula, CuFeS2.
(a) Describe how iron in the ore is removed during concentration of copper metal. (b) State two environmental problems associated with extraction of copper metal.
ANSWERS
The table below shows the relative molecular masses and boiling points of pentane and ethanoic acid
Explain the large difference in boiling point between ethanoic acid and pentane.
ANSWERS
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(b) (i) Cobalt 60 is used to detect the activity of the thyroid gland.
(ii) To sterise equipment/treatment of cancer/radio active Na for disorders in blood circulation/Barium meal for ulcers/detect fractures in bones.
(a) Draw and name the isomers of butyne
(b) State one use of polystyrene.
ANSWERS
(b)Used in packaging - cushions electronics in boxes/insulation/models/ceiling strips/crates or binding.
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December 2024
AuthorMaurice Atika is a teacher and a netprenuer. |
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