SNC2D

Exam Prep QuestionsANSWERS

  1. Fig. 1.1 shows a cross-section through a flower.(IGCSE 2011)

(a)i. State the function of each of the following parts of the flower.

Petal - __Attract pollinators/protection of stamen/stigma______

Anther - _male sexual organ______

(2 marks)

ii. Name the part of the flower that,

Develops into a seed, ______Ovule______

Develops into a fruit, _____Ovary______(2 marks)

(b)Flowers are involved in sexual reproduction. Complete Table 1.1 below to show whether each statement is true for asexual reproduction, sexual reproduction, both or neither.

Use a tick (✓) for a correct statement and a cross (✗) for an incorrect statement. You must write either a tick or a cross in each space in the table.

The first statement has been completed for you.

Table 1.1

Statement / Asexual Reproduction / Sexual Reproduction
Gametes are involved / ✗ / ✓
New individuals are produced / ✓ / ✓
A zygote is produced / ✗ / ✓
Offspring are always genetically identical / ✓ / ✗
  1. Fig 2.1 shows a pin in front of a plane mirror. (O Level 2012)

A ray of light is incident on the mirror as shown.

Fig 2.1

On Fig 2.1,

(a)Draw the normal at the point where the ray is incident on the mirror, (1 mark)

(b)Draw the reflected ray, (1 mark)

(c)Mark the position of the image of the pin with an X. (1 mark)

  1. Hydrocarbons are compounds which contain only the elements hydrogen and carbon.

(a)The simplest hydrocarbon is methane (CH4), which is an important fuel.

(i)State 1 natural source of methane.

______Animals/Volcanoes______(1 mark)

(ii)Complete the following graphical formula of a methane molecule. (2 marks)

(iii)Carbon dioxide and carbon monoxide are compounds released into the atmosphere during combustion.

Describe 1 environmental disadvantage of each compound.

Carbon Dioxide: Greenhouse Gas, also acid rain contributor______

Carbon Monoxide: ______poisonousgas______

(2 marks)

  1. When a light ray passes through a rectangular glass block, the ray is displaced from its original path onto a new path. This is shown in Fig 3.1. (IGCSE 2011/62)

A student is doing an experiment to find out how the value of the displacement distance, d, varies with i, the angle of incidence.

  • He places a glass block on a sheet of paper and draws the outline of the block on it.
  • He Shines a narrow beam of light through the glass block
  • He marks the path of the incident ray on the paper
  • He measures i, the angle of incidence, and records the value in Table 2.1.
  • He marks the new path of the light ray on the opposite side of the block.
  • H removes the glass block from the paper and extends the line showing the original path of the light ray.
  • He measures the displacement distance, d, shown in Fig. 3.1, to the nearest millimetre and records it in Table 2.1.
  • He repeats the experiment, each time using a different angle of incidence, and records the results in Table 2.1.

Table 2.1

Experiment Number / 1 / 2 / 3 / 4 / 5
Angle of incidence, i/˚ / 15 / 28 / 46 / 62 / 77
Displacement d/mm / 5 / 11 / 20 / 32 / 47

(a)Fig 3.2 shows his diagram for experiment.

(i)On fig 3.2, measure i, the angle of incidence, to the nearest degree. Record it in Table 3.1. (1 mark)

(ii)On Fig. 3.2, measure the displacement distance, d, in millimetres to the nearest millimetre, and record it in Table 3.1. (1 mark)

(iii)On Fig. 3.2, measure the length, l, and the width, w, of the glass block in millimetres to the nearest millimetre.

l= ______98______mm

w = ______58______mm(2 marks)

(b)(i) On the graph grid provided below, plot a graph of the displacement distance, d, (vertical axis) in millimetres against the angle of incidence, I, values found in Table 2.1. Use values of i from 0 to 90˚, and values of d from 0-80 mm.

Draw a smooth curve through the points and extend the line to point i = 90˚.

suitable scale chosen and at leas 1 axis labeled correctly; all points plotted +/- small square (allow 1 error); smooth curve drawn and extended to 90˚

(ii) Use your graph to find the value of the displacement distance, d90, when the angle of incidence is 90˚.

Show how you do this on the graph.

d90 = ______60______mm (2 marks)

  1. (a) A student was studying cells under a microscope. She prepared cells from onion epidermis, placed them onto a slide and stained them using iodine solution.(IGCSE 2011/62)

The student wanted to measure the average length of epidermis cells. She placed a ruler with a millimetre scale on the stage of the microscope to find the diameter of the field of view. She looked down the microscope and saw the field of view in Fig 4.1.

(i)How wide is the field of view of the microscope? ___6______mm (1 mark)

(ii)The student removed the ruler and placed her slide under the microscope. She counted 15 cells end to end across the field of view.

Use your answer to (a)(i) to calculate the average length of 1 onion cell. Show your work and don’t forget your units. (2 marks)

6/15 = 0.4 mm

(b) A group of cells is shown below in Fig 4.2.

(i)Make a large drawing of cell A in the space provided below. Label the nucleus and cell wall. (1 mark)

Good quality drawing

(ii)Measure the length of cell A on your diagram at the longest part. See Fig 4.3 which shows the longest part.

length of cell A on my diagram: ___Depends on diagram______mm

using the value for the average cell length from (a)(ii) and the length of cell A on your diagram, calculate the magnification of your drawing. Show your work.

Length taken from students drawing; mag = length/0.4mm; ans according to student reading

Magnification = ______(3 marks)

  1. When a reactive metal is added to a dilute acid, the metal reacts and dissolves and a gas is given off. (IGCSE, 2012/21)

(i)Name one reactive metal that must not be added to a dilute acid.(1mark)

Metal: _____Any Group 1 element______

Explain why this metal must not be added to the dilute acid below:

Reference to explosive/reacts violently/corrosive substances splashing into skin/eyes

(ii)Fig 5.1 shows how a student tested the gas given off when magnesium was added to dilute hydrochloric acid.

State and explain what the student observed when he carried out this test.

Observation: ____pops______

Explanation: ____hydrogen given off______

(2 marks)

  1. Some types of fireworks are made by filling cardboard tubes with firework mixture. Firework mixture is made from several solid substances, which have been powdered and mixed together.

Fig 6.1 Shows a typical firework.

When the paper fuse is lit, exothermic combustion reactions occur inside the firework.

(a)(i) State TWO forms of energy that are released when the firework mixture reacts.

  1. _____heat______
  1. ____light and or sound______

(b)Some firework mixtures contain aluminum which is oxidized when the firework is lit.

Table 6.1 shows the numbers of protons and electrons in four particles, A, B, C and D, which are involved in the oxidation of aluminum.

(i)Atoms of the element aluminum have the proton number 13.

State and explain which particle, B, or D, in Table 6.1 is an atom of aluminum.

Particle: ______B______

Explanation: ______B is uncharged/neutral/also has 13 electrons/number of protons = number of electrons______

(ii)State and explain which two particles in Table 6.1 could be found bonded together in aluminum oxide.

Particles _____A______and _____D______

Explanation: ___A is ion of oxygen and D is ion of aluminum and metals will bond ionically with non metals

(c)Firework mixtures contain the compound potassium perchlorate, KClO4

When potassium perchlorate is heated, a colourless gas is given off which re-lights a glowing splint.

(i) State the name of the gas: ______Oxygen______

8. A student drew the following diagram to show the transmission of light through an optical fibre. Assess the accuracy of the diagram.

Answers:

9. The Alberta Energy website states “Every two weeks Alberta produces enough coal to fill the Rogers Centre in Toronto”. The Rogers Centre is a Baseball/Football stadium.

  1. Assuming the volume of the Rogers Centre is 1.6 million m3. All the coal produced was burned, and remember that coal is mostly carbon, in the space below estimate the mass (in tonnes) of carbon dioxide produced in a year. You can assume that a m3 of coal has a mass of about 1 tonne (1000kg) (5 marks) MSC 2008
  1. The diagram shows scientific principles that can be used in communication.

What is the name of the scientific principle that Z represents?

(a)Refraction

(b)Binary transmission

(c)Total Internal Reflection

(d)Absorption

11. When a TV interviewer in Sydney Australia conducts a live interview with a person in New York, a satellite is used. The signals transmitted via the satellite travel at a speed of 3 x 108 m/s between the two cities. A person watching the interview observes a noticeable delay in the communication process.

When a person in Sydney talks to a person in New York by phone, the signals pass through optical fibres between the two cities, traveling at a speed of 2 x 108 m/s, and there is no noticeable delay in the communication process.

Why is the delay noticeable in the TV interview but not in the phone conversation?

(a)The phone signals travel more efficiently through optical fibres than electromagnetic waves do through a vacuum.

(b)Computers in a phone system make the process faster than satellite systems.

(c)Satellites move so fast that the TV signals take time to catch up with them

(d)The phone signal travels less distance than the TV signals

  1. A heart medication has a coating which breaks down in acidic conditions. In which part of the digestive system will the coating break down?

(a)mouth

(b)stomach

(c)small intestine

(d)large intestine

11. Which of the following instructions always applies when working with household pesticides?

(a)Do not use indoors

(b)Wash hands after use

(c)Store in a cool dark place

(d)Keep away from naked flames

12. What feature of electromagnetic waves allow them to be used for communication?

(a)They can be used in optical fibres

(b)They can travel at very high speeds

(c)They can be detected using a simple antenna

(d)They can pass through the atmosphere without interference

13. Which statement makes a correct comparison between the use of an optical fibre and a copper wire for communication?

(a)Both the optical fibre and copper wire transmit signals using electromagnetic waves

(b)It is cheaper to send the same amount of data through a copper wire than through an optical fibre

(c)More data can be transmitted per second through an optical fibre than through a copper wire

(d)Electromagnetic waves are emitted from the optical fibre making the data less secure than data transmitted through the copper wire.