Skills Your Unit 1 exam - … · ˜˚˛˝˚˝˙ˆˆˇ ˘ ˚ ˙ ˝ ˘˚ ˙ ˛˝ 42 Unit 1 Skills Your Unit 1 exam Your Unit 1 exam will be set by Pearson and could cover any of the

Had a look Nearly there Nailed it!

42

Unit 1

Skills

Your Unit 1 examYour Unit 1 exam will be set by Pearson and could cover any of the essential content in the unit. You can revise the unit content in this Revision Guide. In this Revision Guide, pages covering Structure and functions of cells and tissues have the heading “Biology”, those covering Periodicity and properties of elements are headed “Chemistry” and those covering Waves in communication are headed “Physics”. The section uses selected content and outcomes to provide examples of ways of applying your skills.

Exam skills

Recalling information Revise this on page 43

”Calculate” or “write” questions See some examples on page 44

”Explain” questions These are covered on page 45

Long-answer questions Revise this skill on page 46

”Describe” or “discuss” questions See some examples on page 47

”Compare” questions Revise this on page 48

Showing your working Revise this skill on page 49

Exam checklistFor your exam, make sure you:

Get a good night’s sleepHave a black pen you like, a pencil and at

least one spare of eachHave double-checked the time and date

of your examAlways show your workingRemember to use the formula sheet and

any other useful information you are given at the end of the paper

Use any extra time to check your answers

Check the Pearson websiteThe questions and sample response extracts in this section are provided to help you to revise content and skills. Ask your tutor or check the Pearson website for the most up-to-date Sample Assessment Material and Mark Scheme to get an indication of the structure of your actual paper and what this requires of you. The details of the actual exam may change so always make sure you are up to date.

Visit the Pearson website and find the page containing the course materials for BTEC National Applied Science. Look at the latest Unit 1 Sample Assessment Material (SAM) to get an indication of: • the number of papers you have to take• whether a paper is in parts• how much time is allowed and how many marks are allocated• what types of questions appear on the paper• what additional information, such as a periodic table or formula sheet, may

be given to you in the exam.

Your tutor or instructor may already have provided you with a copy of the Sample Assessment Material. You can use these as a ‘mock’ exam to practise before taking your actual exam.


43

Unit 1Skills

‘Give’, ‘state’ and ‘name’ questions‘Give’, ‘state’ and ‘name’ questions require you to recall one or more pieces of information. ‘Label’ questions are similar, except you need to add information to a graph or diagram.

The graph below shows the signal produced when a microphone picks up a pure note. Give the amplitude of this electrical wave.

Amplitude = 2.6 mV

1 mark

Sample response extract

State two advantages of sending signals by optical fibre cable rather than using copper wires.

1 There is less attenuation so the signal travels further.2 It is more secure as fibres cannot be hacked into.

2 marks


This question asks for two advantages,

so just two brief statements are needed.

The answer clearly identifies advantages by using the words ‘less and ‘more’.

Mark on the graph to show where you are taking your measurement – in this case, from the central rest value to the peak.

The answer is stated with an appropriate degree of accuracy and the unit is included.

Revise optical fibres on page 37.

Links

Revise how microphones pick up sound on page 31.

Links

A soup was identified as causing food poisoning. Microscopic examination showed that some cells had cell walls and others did not. The cells with cell walls seemed to be two types: one from plant material and one was bacteria. State features that would distinguish the plant cells from the bacterial cells.

Bacteria Plantssmaller than plant cells larger than bacteriajust an area of DNA membrane-bound nucleus7OS ribosomes 8OS ribosomespresence of plasmids no plasmidspeptidoglycan cell wall cellulose cell wallpresence of capsule outside cell wall

no capsule outside cell wall

4 marks


This question is asking you to list features you would find in a plant cell

and in bacterial cells.

There are 4 marks for this question,

so you need two distinguishing features for bacterial cells and two

for plant cells.

Revise the difference between bacteria and

plant cells on pages 3 and 4.

Links

A table is a good way to display this

information.

For plant cells, you could also mention

vacuole, chloroplasts and lack of capsule; for bacteria, pili and or flagella.

3

2

1

0

1

–2

–3

0 0.2 0.4

Time (ms)

0.6 0.8

period, T

1

Mic

roph

one

sign

al (

mV

)

State what is meant by the term ‘covalent bond’.


44

Unit 1

Skills

‘Calculate’ and ‘write’ questions ‘Calculate’ questions require you to obtain a numerical answer, showing relevant working. You must include the unit, if the answer needs one. ‘Write’ questions often ask for an equation.

Nitric acid is used to manufacture fertilisers. A sample of 20.0 cm3 of nitric acid required 17.8 cm3 of 0.250 mol dm–3 potassium hydroxide, KOH, to exactly neutralise it. The equation for the neutralisation reaction is: HNO3 + KOH → KNO3 + H2O

Calculate the concentration of the nitric acid, in mol dm−3.

A researcher has a photomicrograph of a blood smear, but unfortunately did not record the magnification of the image. However, they do know that they had previously calculated the diameter of the red blood cell as 8 micrometres. Calculate the magnification of the image.

Magnification = image size

real object size

Magnification = 4 millimetres

8 micrometres

Magnification = 4000

8 = ×500

3 marks


Revise concentration

calculations on page 24.

Links

For the microphone signal shown on page 43, calculate the frequency of the sound wave that caused it.

f = 1T =

1(0.4 ms) = 2.5 Hz

3 marks


A sound check is done with a microphone just 20 cm away from a guitar soundboard. The musician then changes position so that the distance becomes 60 cm. Calculate by how much this will change the intensity of the sound picked up by the microphone.

I2I1 =(

r1r2

)2 = (20/60)2 = (1/3)2 = 1/9

Intensity will be 9 times smaller at a distance of 60 cm.

2 marks


In ’calculate’ questions you need to select the right formula and show you can apply it.

The inverse square law formula is correctly applied, the steps of working are shown, and the answer is then stated clearly.

Mark on the graph on page 43 to show

how you measure the period correctly.

This question has three steps: recalling the

formula for frequency, measuring the period from

the graph, and then calculating the frequency

from it, including the correct unit.

Revise wave frequency on page 32.

Links

Remember that you need to make sure the units are

the same. There are 1000 micrometres in a millimetre.

Magnification is a ratio so it does not have units.

red blood cell

You need to measure the diameter of the red blood cell in the image.

Revise sound amplitudes on page 33.

Links


45

Unit 1Skills

‘Explain’ questions‘Explain’ is probably the most common type of question. They require you to justify a point, using a clear process of reasoning. For maths questions, you must show your working. Some questions ask just for two things to be linked while others look for a longer series of connections and reasons.

Explain how a closed-ended tube can act as a resonator, what determines the fundamental frequency, and which harmonics can also be produced.

The closed end of the tube forces a node because no displacement can take place there. An antinode forms at the open end because the free air allows big displacements. The fundamental mode has a quarter wavelength in the pipe, and other harmonics with an odd number of quarter wavelengths in the pipes are also possible.

4 marks

Sample response extractAlthough the question asks about frequency, the answer needs to talk about wavelengths.

It is not sufficient just to say that a

stationary wave forms or to mention nodes

and antinodes. You need to explain why or

how they are created.

This question has 4 marks and three

sections, so be sure to tackle all the parts

and to make at least four separate points.

Revise stationary waves on page 36.

Links

The ionic compound magnesium fluoride, MgF2, is used in lens manufacture for telescopes.

(a) Draw an electronic configuration diagram of the ions in magnesium fluoride

(b) Explain, using ideas about structure and bonding, why it has a high melting point.

The structure consists of a giant ionic lattice, so contains many strong ionic bonds. These bonds are electrostatic attractions between oppositely charged ions. In order to melt the compound, these attractions have to be broken. This requires a lot of heat energy, hence the high melting point.

2 marks

xx

xx

x

x

xxx

xx

x

x

x

F–

F–

Mg2+


4 marks


’Draw’ and ‘Explain’ may be parts of the same question. You might find that the drawing helps you with the ‘Explain’ part of the question.

The answer not only discusses the structure and bonding in the compound but links these ideas to the energy needed to melt it to make sure the high melting point is explained.

Digital television and radio transmission is allowing many more channels to be broadcast and received within the available frequency bands.

Explain how this is achieved, and comment on the compromises involved in analogue to digital signal conversion.

For more on the difference between

analogue and digital signals, see page 39.

Links

You should clearly and logically outline the differences between analogue and digital broadcasts.


46

Unit 1

Skills

Answering longer questionsSome questions build on a topic, and combine several command words and assessment outcomes, such as in the example below.

The graph shows the first ionisation energies of elements in period 3.

(a) Write an equation to show the first ionisation of sulfur.

S(g) → S+(g) + e−

(b) Explain the trend in first ionisation energy across the period.

Across the period the ionisation energy increases. This is because the number of protons in each successive element increases, so the nuclear charge increases. In each element the electron removed comes from the same shell, with similar shielding from the nuclear charge by the inner shells. Hence the electrostatic attraction of the nucleus to the outer electrons increases across the period.

(c) Explain the slight anomaly in the trend, where sulfur has a lower first ionisation energy than phosphorus.

The electron removed in phosphorus comes from a singly occupied p-orbital, 3p3. The electron removed from sulfur comes from a p-orbital containing a pair of electrons, 3p4. The pair of electrons repel each other so one electron is now easier to remove, resulting in a slight drop in first ionisation energy.

2 marks


4 marks


2 marks


You may have to interpret data from graphs or tables and use it to support explanations of key chemical concepts.

Write the equation clearly. If you make a mistake, cross it out and write the equation again. Remember to include state symbols.

If you are asked to explain a trend, outline the trend first.

You may find it helpful in questions like this to work out the electronic configuration of each element, using ‘electrons in boxes’.

First ionisation energies of Period 3 elements

Fir

st io

nisa

tion

ene

rgy

(KJ/

mol

)

Element

0

200

400

600

800

1000

1200

1400

1600

Na Mg Al Si P S Cl Ar

Explain why the second ionisation energy of an element is always greater than the first ionisation energy.

Take care with precision of language in an answer to this type of question. The attraction the nucleus has on the electrons increases, but not the nuclear charge.

Skills Your Unit 1 exam - … · ˜˚˛˝˚˝˙ˆˆˇ ˘ ˚ ˙ ˝ ˘˚ ˙ ˛˝ 42 Unit 1 Skills Your Unit 1 exam Your Unit 1 exam will be set by Pearson and could cover any of the

Documents