IGCSE Test Questions
1. The table shows the solubility of lead nitrate in water. The units are grams of lead nitrate in 100 grams of water.
Plot a graph of the solubility of lead nitrate in water using the axes provided.
Use it to answer the questions which follow.
(i) What happens to the solubility of lead nitrate as the temperature increases? ___________________________________________________________
(ii) What is the solubility of lead nitrate, in 100g of water, at
30 °C _______________________________________________
50 °C _______________________________________________
(iii) A saturated solution of lead nitrate was made at 50 °C using 100 g of water, and this was then allowed to cool to 30 °C. What happened as the solution cooled? ___________________________________________________________ ___________________________________________________________
ANSWERS: (i) It becomes more soluble.(ii) ~61g and ~84g (iii) The lead nitrate solidifies.
2. Everyday experiences can often be explained using scientific ideas about the way particles are arranged in solids, liquids and gases. (a) In the boxes below, show how the particles are arranged in a typical solid, liquid and gas (in each case, use the symbol X to represent each particle).
(b) When a jar of coffee is opened, people in all parts of the room soon notice the smell. Use ideas about particles to explain how this happens. _________________________________________________________________ _________________________________________________________________
(c) Salt soon disappears when stirred in water. Explain why all parts of the water then taste salty. ____________________________________________________________ ________________________________________________________________
ANSWERS: (b) (c) Both answers should include something about diffusion of particles.
3. An element may be shown as
How many electrons does one atom of this element contain?
4. What process changes a chlorine atom, Cl, into a chloride ion, Cl-?
A electron gain
5. Which equation represents the combustion of hydrogen gas?
A H2 + O2 = H2O2
6. The equation for the burning of butane is shown below.
2C4H10 + 13O2 ÷ 8CO2 + 10H2O
How many moles of water are formed when one mole of butane burns completely?
7. An element has the electronic structure 2.8.3. It may be deduced that the element
A is in group 2 of the Periodic Table
8. What is added to water to prevent tooth decay?
9. acid + alkali = salt + .......................................
What is missing from the above equation?
A carbon dioxide
10. How should the following reaction be written as a balanced symbol equation?
carbon + carbon dioxide = carbon monoxide
A C + CO2 = 2CO
11. Gases, unlike solids, may be easily compressed because
A gas molecules are softer than those in solids
12. Chlorine is added to the domestic water supply in order to
A soften the water
13. Which of the following is a noble gas?
14. The table shows the densities of some Group 1 metals.
Which metal sinks in benzene (density of liquid = 0.88 g/cm3) but floats in nitrobenzene (density of liquid = 1.2 g/cm3)?
15. The table shows the electronic structures of hydrogen and helium.
What is the electronic structure of lithium?
A 1 1 1
16. What happens when ice melts?
A Water molecules change to hydrogen and oxygen atoms.
17. This table shows the melting points and boiling points of four substances.
a.) Which substance is liquid at 100 °C? ___________
b.) Hydrogen reacts explosively with oxygen to form water. Use a diagram to show the bonding in a water molecule. Draw the outer electrons only (ie. valency electrons).
ANSWER: a.) C b.)
18. What causes the intake or release of energy in an exothermic or endothermic reaction?
A Electrons escaping or being drawn in
19. What is the equilibrium of a reversible reaction?
A The point at which the yield in each direction is the same
20. A pure substance which cannot be split up by chemical reaction is called...
A a compound
21. Elements that have been mixed can still be separated
22. Which of the following is NOT a property of a compound?
A It is difficult to separate out the elements in it
23. Which of these statements about the periodic table is untrue?
A Elements are arranged in increasing order of atomic number
24. What are the horizontal rows of elements in the periodic table called?
25. How many electrons do group VI elements have in their outer shell?
A It varies
26. When group I elements react, they will...
A gain two electrons
27. What is the name given to water loss to the atmosphere by green plants?
28. Which of these statements about water uses is FALSE?
A Water is used as a coolant
29. What are gases that contribute to global warming called?
A warming gases
30. Which of the sections of the Earth`s core is molten?
31. Tectonic plates sliding past one another can cause...
32. In single-celled organisms, gaseous exchange takes place through
the cell membrane
33. How are lungs adapted for efficient gaseous exchange?
A They have thin, moist membranes with a large surface area
34. How do mammals respire?
35. Enzymes are...
36. Can enzymes help to speed up reactions?
37. Which of these factors does NOT speed up transpiration?
A High temperature
38. What do phloem vessels do?
A Transport food through a plant
39. In addition to transporting water, what other function does a xylem vessel perform?
A Gives strength to the stem
40. Does an organism which reproduces asexually need another organism to reproduce with?
41. Is the offspring of an asexual organism genetically identical to its parent?
42. Cross-pollination takes place solely within one individual plant
43. What are the two main functions of fruit for a plant?
A To disperse and protect the seeds
44. Put these in order of size, smallest first:
A Gene, cell, chromosome, base, nucleus
45. Which of these cannot be a result of genetic mutation?
46. If the climate changes very suddenly, what is the most likely effect on species which live in and are adapted to the previous climate?
A Immediate evolution of the species to adapt to the conditions
47. Evolution can lead to the creation of new species
48. Evolution takes place...
A In the space of one generation
49. Which of the following did Darwin specify to be cruicial to the Theory of Evolution?
A Survival of the fittest of each species
50. What effect does temperature have on enzymes?
A Boiling will denature them, as will being too cold
51. The laws of reflection at plane surfaces include...
A the angle of incidence equals the amplitude
52. The image produced by a pinhole camera is always...
A Black and white
53. An object on Earth has a weight of 420 N and a mass of 42 kg. What is the mass and weight of the object on the moon, if the moon's gravitational attraction is one sixth that of earth?
ANSWER: B Comment: Mass remains constant and does not change. Weight however changes according to the gravitational field strength. Therefore weight = 420 × 1/6 = 70 N
54. When an object is placed in a liquid (water) it displaces a volume of liquid equal to ________________.
ANSWER: its own volume. Comment: If an object is placed in a liquid, the level of the liquid rises by the same volume as that of the object. This is a useful way of determining the volume of objects with irregular shapes.
55. An athlete runs 240 m in 30 seconds. His average speed (in m.s-1) is
ANSWER: B Comment: Average speed = distance/time = 240m/30s = 8 m.s-1
56. The pressure in N.m-2 exerted by a 60 kg person standing on a floor where the contact area is 100 cm2 is:
A 0.6 kPa
ANSWER: C Comment: P = F/A = 600 N/0.01 m2 = 60 000 Pa = 60 kPa Note: force = weight exerted by a person = mass × 10 = 60 kg × 10 = 600 N (Area of 100 cm2 = 0.01 m2)
57. A stone dropped from a helicopter takes 10 seconds to hit the sea below. What is its final velocity? (Assume that the acceleration due to gravity is 10 m.s-2)
A 10 m/s
ANSWER: B Comment: velocity = acceleration × time = 10 m.s-2 × 10 s = 100 m.s-1 (The acceleration of the falling stone is taken as the acceleration due to gravity i.e. 10 m.s-2.)
58. Which one of the following is a non-renewable source of energy?
ANSWER: B Comment: There are limited deposits of uranium on the earth.
59. A radio converts:
A electrical energy into light energy.
ANSWER: D Comment: Most energy changes involve energy changing from one form into two or more different forms. Electrical energy is mainly converted into sound via sound waves.
60. Which of the following are advantages of hydro-electric power stations over coal power stations?
A Use of renewable energy sources and pollution free
ANSWER: A Comment: The use of renewable energy sources and the fact that there is no sulphur or carbon dioxide being released into the atmosphere. The running costs are also cheaper.
61. What is the reading on ammeter C? (Assume the bulbs are identical)
A 1 A
ANSWER: B Comment: The current splits in half because the lamps offer equal resistance.
62. The colour of a pure red rose in white sunlight is a result of the fact that:
A the rose absorbs red light only.
ANSWER: C Comment: Red light is the only component of the visible spectrum which reaches the eye.
63. A ray of light strikes the surface of a mirror at an angle of incidence of 40°. The angle of reflection is:
ANSWER: A Comment: The law of reflection: the angle of incidence is equal to the angle of refraction.
64. White light passes through a triangular prism and a band of colour is observed where it emerges. The phenomenon that occurs in the prism and the band of colour are respectively known as:
A dispersion and spectrum.
ANSWER: A Comment: The splitting up of white light into its component colours is known as dispersion and the band of colour is called the visible spectrum.
65. Which one of the following is not a property of images formed in a plane mirror?
A They are laterally inverted
ANSWER: B Comment: The image in a plane mirror is the same size as the object.