9702/01 Paper 1 Multiple Choice

1 Which of the following is a scalar quantity? 

A acceleration    B mass      C momentum     D velocity

Answer
1-B
because mass has magnitude only


2 The unit of work, the joule, may be defined as the work done when the point of application of a force of 1 newton is moved a distance of 1 metre in the direction of the force. Express the joule in terms of the base units of mass, length and time, the kg, m and s.

 A kg m–1 s2        B kg m2 s–2        C kg m2 s–1       D kg s–2

Answer

2-B
Work done = Force*distance
kgms^-2 *m = kgm^2 s^-2


3 Two forces, each of 10 N, act at a point P as shown in the diagram. The angle between the directions of the forces is 120°.

3-B
Using cosine rule: c^2 = a^2 + b^2 +2abcosC
c^2 = 10^2 + 10^2 +2(100)cos 120
C = 10 N



4 Which experimental technique reduces the systematic error of the quantity being investigated?


 A adjusting an ammeter to remove its zero error before measuring a current
 B measuring several internodal distances on a standing wave to find the mean internodal distance
 C measuring the diameter of a wire repeatedly and calculating the average
 D timing a large number of oscillations to find a period


4-A
Basic concept that a systematic error can be reduced by checking for zero error.



5 A student makes measurements from which she calculates the speed of sound as 327.66 m s–1. She estimates that her result is accurate to ±3 %.
Which of the following gives her result expressed to the appropriate number of significant figures?

A 327.7 m s–1     B 328 m s–1    C 330 m s–1     D 300 m s

5-C
because 3% of 330 = 10 m/s
and speed of sound = 330 m/s



6 A steel rule can be read to the nearest millimetre. It is used to measure the length of a bar whose true length is 895 mm. Repeated measurements give the following readings.

6-B
Accuracy: closeness of the measured values to the true value
Precision: closeness of measured values.


7 A projectile is fired at an angle α to the horizontal at a speed u, as shown.

7-C

For vertical component: v = u +at
v = usina - gt
and in horizontal component v = u cos a 

8-C
In the first 1/3 of the graph, velocity is increasing hence the gradient should be increasing steeply.
In the second 1/3 of the graph, velocity is constant so gradient should be constant, hence a straight line.
In the last 1/3rd of the graph, gradient is decreasing hence line should be least steep.

Areas X and Y are equal. This is because
A the ball’s acceleration is the same during its upward and downward motion.
B the speed at which the ball leaves the surface after an impact is equal to the speed at which it returns to the surface for the next impact.

C for one impact, the speed at which the ball hits the surface equals the speed at which it leaves the   surface
.
 D the ball rises and falls through the same distance between impacts.

May June 2004 Complete Work Solution with Examiner Report 9702_s04_qp_2.

1 (a) State the difference between a scalar quantity and a vector quantity.

scalar: magnitude only

 vector: magnitude and direction (allow scalar with direction)
 [2] (allow 1 mark for scalar has no direction, vector has direction)

Examiner report : 
Almost all candidates stated satisfactorily the difference between scalar and vector quantities.
Candidates should be encouraged to use correct terminology. For example, ‘magnitude’ rather
than ‘size’ or ‘value



Q2) (b) Two forces of magnitude 6.0 N and 8.0 N act at a point P. Both forces act away from point P and the angle between them is 40°. Fig. 1.1 shows two lines at an angle of 40° to one another.

Most candidates did construct a parallelogram or a triangle with directional arrows on the vectors.
There were some very good, accurately drawn figures but many wrongly assumed that the lengths
of the given dotted lines were appropriate for the sides of the parallelogram or triangle. They then
gave the answer as the length of the ‘resultant’, without any regard for scale. A significant number
calculated the resultant, having drawn an appropriate diagram. Others, however, disregarded the
instruction and calculated the resultant, without drawing even a sketch diagram


2 Fig. 2.1 shows the variation with distance x along a wave of its displacement d at a particular time.

The wave is a progressive wave having a speed of 330 m s–1. (a) (i) Use Fig. 2.1 to determine the wavelength of the wave. wavelength = ................................... m


λ = 0.6 m

With few exceptions, candidates read correctly the wavelength from the graph and completed the

calculation to obtain the frequency.

(ii) Hence calculate the frequency of the wave. frequency = .................................... Hz [3]


frequency (= v/ λ )
                = 330/0.60 = 550 Hz


[3] (use of c = 3 x 108 ms-1 scores no marks)


(b) A second wave has the same frequency and speed as the wave shown in Fig. 2.1 but has double the intensity. The phase difference between the two waves is 180°. On the axes of Fig. 2.1, sketch a graph to show the variation with distance x of the displacement d of this second wave. [2]


As 


We can write it as: 
Where  is just a random constant (and so doesn't affect by how many times intensity increases/decreases as it remains the same)

So for when amplitude increases by for example 2 times, then yes intensity increases by 4 times

You could then in a way rewrite the equation as:



Where  is another random constant

And hence 

So the amount of times intensity is increased by, amplitude is increases by the square root of that factor.
eg Intensity increases by 2 times, amplitude increased by 

Q1 .A sample of 0.025 mol of the chloride of an element Z was dissolved in distilled water and the solution made up to 500cm3. 12.5cm3 of this solution reacted with 25cm3 of 0.1 moldm-3 silver nitrate solution. What is the formula of the chloride?


A. Z2Cl    B. ZCL   C. ZCl2   D. ZCl4


Help:

Silver (I) Chloride reacts with Chloride to give silver (I) chloride percipitate : 

                                Ag+ (aq)    +   Cl- (aq) -------------> AgCl (s)

The amount of Aq+ used? = Concentration X volume

                                                       = o.1 (mol dm^-3)  x  (25/1000) (dm^3)
                                                      = 2.5 x 10^-3

Since 1 mole of Ag+ react with 1 mole of Cl- ,  Amount of Cl- present in 12.5 cm^3     =2.5x10^-3/12.5 x 500
                                                                                                                                                                             = 0.1 mol


Since 0.025 mole of compound contain o.1 mole of chloride, I mole of the compound therefore contain
0.1/0.025 = 4 mole of chloride. 

The Formula for the compound is ZCl4

Answer is D

Q2)  In the absence of a catalyst, ammonia burns in an excess of Oxygen to produce steam and nitrogen. What is the volume of oxygen, remaining when 60 cm^3 of ammonia is burnt in 100 cm^3 of oxygen, all  the volume being measured at the same temperature and pressure?

A 25 cm^3   B 35cm^3  C 40 cm^3  D 45 cm^3  E 55cm^3



Help

4 NH3 (g)  +  3O2 (g)  ----------> 2N2 (g) + 6 H2O (g)


60 cm^3 of NH3  requires 3/4 X 60 = 45cm^3 of O2

Therefore, Volume of Excess O2= 100-45=55 cm^3



Q4 A sample of 10dm^3 of populated air is passed through the lime water so that all of the carbon dioxide present is precipitated as calcium carbonate. The mass of calcium carbonate formed is  0.05 g. What is the percentage, By volume of  carbon dioxide in the air sample?

{Relative Atomic Masses C, 12 O 16; Ca 40; I mole of gas under the experimental conditions has a voulme of 24 dm^3}


A 0.03%  B  0.05  %   C 0.12%  D 0.3 %


Help

Ca(OH)2 (aq)  +  CO2(g)-----------> CaCO3 (s) + H2O

Amount of precipitated = 0.05/40+12+3 x 6
                                                 =  5.0 X 10^-4 x 24
                               
Therefore the volume of CO2= 5.0  x 10^-4 x 24
                                                = 1.2x10^-2  dm^3

Therefore, % volume of CO2 =1.2 x 10^-2 /  10    X 100
                                                = 0.12

Answer C


Q5

A sample of 2.00 g of iron (III) sulphate, Fe2(SO4)3, is dissolved in water to give 100 cm^3 of aquous solution. What is the concentration of SO4^2- ions? { The relative formula (molecular) mass of Fe2(SO4)3 IS 400} 


A 1.5 x 10^-3 mol dm^-3
B   5  x 10^-3 mol dm^-3
C 1.5 x 10^-2 mol dm^-3
D 5    x 10^-2 mol dm^-3
E 1.5 x 10^-1 mol dm^-3


Help

1 mole of Fe2 (So4)3 gives 3 mole of SO4^2-  ions.
Therefore, Concentration of SO4^2- = (2.00/400  /   100/1000)   X  3
                                                           = 0.15 mol dm^-3


Q6

What is the volume of Oxygen is required for the complete combustion of mixture of 5 cm^3 of CH4 and 5 cm^3 of C2H4?

A 5cm^3   B 10 cm^3  C  15 cm^3  D 20 cm^3 E 25 cm^3

Help

CH4 (g) + 2O2 (g)--------> CO2(g) + 2H2O (l)
C2H4 (g) + 3O2(g)------->2CO2 (g) + 2H20 (l)

Volume of O2 required to burn 5 cm^3 of CH
= 2x5=10cm^3
Volume of O2 required to burn 5 cm^3 of C2H4
= 3 x 5 =15 cm3
Total Volume of O2 required
= 10+15=25cm^3

Answer E



Q7 In which of the following reactions does hydrogen behave as an oxidizing agent?

A H2 + Cl2---------> 2HCl
B C2H4 + H2------->C2H6
C C2H5CHO + H2------->C2H5CH2OH
D N2 + 3H2-------->2NH3
E 2Na + 3H2-------->2NaH



Help
An Oxidising

Topical Mcq Chemistry A level- Atoms, Molecules and Stoichiometry

Q1 .A sample of 0.025 mol of the chloride of an element Z was dissolved in distilled water and the solution made up to 500cm3. 12.5cm3 of this solution reacted with 25cm3 of 0.1 moldm-3 silver nitrate solution. What is the formula of the chloride?

A. Z2Cl    B. ZCL   C. ZCl2   D. ZCl4


Help:

Silver (I) Chloride reacts with Chloride to give silver (I) chloride percipitate : 

                                Ag+ (aq)    +   Cl- (aq) -------------> AgCl (s)

The amount of Aq+ used? = Concentration X volume

                                                       = o.1 (mol dm^-3)  x  (25/1000) (dm^3)
                                                      = 2.5 x 10^-3

Since 1 mole of Ag+ react with 1 mole of Cl- ,  Amount of Cl- present in 12.5 cm^3     =2.5x10^-3/12.5 x 500
                                                                                                                                                                             = 0.1 mol


Since 0.025 mole of compound contain o.1 mole of chloride, I mole of the compound therefore contain
0.1/0.025 = 4 mole of chloride. 

The Formula for the compound is ZCl4

Answer is D

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9701/01 Paper 1 Multiple Choice May/June 2008

Q1 For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct.

1 In the Basic Oxygen steel-making process the P4O10 impurity is removed by reacting it with calcium oxide. The only product of this reaction is the salt calcium phosphate, Ca3(PO4)2. In this reaction, how many moles of calcium oxide react with one mole of P4O10?

A 1          B 1.5          C 3         D 6 

Solution

A level Chemistry Practical

1,I have a trouble in making deductions ,for cation and anion tests!
2,I also have trouble in making observations for gases,because i fail to understand for which reaction should i place the litmus papers on the test tube. :? 

Place the litmus paper whenever you see the mixture in the test tube bubbling.

The Qualitative analysis is given at the back. First fall arrange your test tube in an order which you can work with quickly, don't just put them randomly to mix them up! Secondly, take small amounts of liquids in the test-tubes to get faster results. You only need an approximate volume to the one given in the qst. See the qualitative analysis for the reagent that you are using. For example you are using sodium hydroxide (aq) then see the column of sodium hydroxide(aq) and try to match the colour changed that happened, if any. Thats all that you need to do. Apart from this only practice will help.

then you should keep calm
dont just jump onto conslusions
slowly and carefully
take care not to be too slow too!!!
and as u go on writing  your observations , write somewhere next to it the ions u would go for i mean white precipitate for Al , Zn and Ca when NaOH is added
i think i am right
anyways
u gotta write it and then strike out as u proceed in the end ur left with the answer!

A level Biology Practical notes!!

GRAPHS!
1.the value which is varying is always on the y-axis while the constant value is on the x-axis.
2.no unbroken lines
3.it must be neat and thin
4.the points can be joined using a ruler or by hand
5.do not draw beyond the plotted points.
6.blobs or centre points more than 1mm are NOT acceptable
7.if zero is present in the reading, ur graph MUST pass through zero.
8.label both axis!
9.use appropriate units
10.use appropriate scale
11.use sharpened pencil to plot
12.plot the dots within circles, of equal sizes, must be clear and not too big.

SOURCES OF ERRORS!
1.temp nt controlled
2.pH not controlled or nt measured accurately
3.difficulty in judging the colour.
4.difficulty in having the same time
5.inaccuracy in preparing serial dilution
6.inaccuracy of equipment, fr e.g. pipette/syringe
7.too short time.
8.evaporation of the solution which can cause the concentration to change.

LIMITATIONS OF ERRORS!
1.measure the volume accurately using syringe with narrow range of calibration
2.repeat more times at each pH/conc./temp
3.use range of pH/conc./temp
4.accurate specific measuring devices
5.use colorimeter to measure the degree of colourness.
6.use buffer to control pHs
7.use of water bath/thermostat to control temp
8.use thermometer to measure the temp.
9.thermostatically controlled environment.
10.repeat with each conc.
11.volume of the sample(e.g. enzyme/substrate) must be the same..cuz as volume increases, conc also increases
12.keep only one factor different, and all others must be the same.

Reliability.....take minimum of 3 readings!
repeat with mre pH/conc/temp
and find out their mean
Accuracy.....seing electronic thermostat
use of pippettes instead of measuring cylinders

KEY
1)read the whole question till the end
2)decide number of readings to take
3)don't go for more or less than 3 readings per conc/vol of any ques.
4)make a table
5)write down the UNITS in each coloumn of the table...e.g. conc/cm^3 , temp/°C

MICROSCOPY!!!

1)propotion of thickness must be correct.
2)draw the organelles where u see them, dont just draw anywhere within the cell! never draw what u know.
3)whenever u see the plant cells, draw the cell walls.
4)IN PLAN DIAGRAMS, NO DRAWING OF ANY CELLS, AND NO SHADING...if u'll do either of them, u'll lose the whole mark!!
5)when asked to draw 2 cells, draw the ones that are easiest to draw. and dont draw more then 2 cells!
6)fraw the adjacent (touching) cells.
7)drawing should be large, unshaded.
8)in plan diagrams show the relative thickness of each layer.
9)draw the exact shape, if its oval or round or has wavy outlines
10)label the diagram...simplest thing to label is cytopasm, nucleus and cell membrane.
11)if its a trachea cell, then label goblet cells, cilia, blood vessels, muscular tissue, cartilage cells (lacunae)
12) when asked to compare 2 diagrams....make a table (drawing a table itself has 1 mark!)....put atleast one similarity

ERRORS IN MESUREMENTS!
1)irregular in shape
2)difficulty in focusing
3)preperation is squashed

and yeahhhh one more thingg, the values must be whole numbers!!! e.g if its 8.5mm u round it off to a whole number which is 9!!

Simple dilution and Serial dilution??

Serial dilution is actually very easy. If you have 30cm3 of 10% enzyme solution (example) you take 20cm3 of that 10% in put it in beaker 1. From this 20cm3 in beaker 1, take another 10cm3 and place it in beaker 2 and add 10cm3 of water. This dilutes the solution into 5%. Do the same thing for beaker 3, take 10cm3 of the 5% solution and add 10cm3 of water in beaker 3 to get 2.5% solution.
This way you have:
Beaker 1 - 10% enzyme solution
Beaker 2 - 5% enzyme solution
Beaker 3 - 2.5% enzyme solution



Usually you get a specimen on a slide or a photomicrograph to draw a plan diagram. 

For a low power drawing 

1. you must not draw individual cells when drawing a plane diagram.

2. draw only the outline of tissues.(don’t shade, draw thinner continuous lines.)

3. When drawing a specimen on a slide you can use high power to clearly see where the edges of

tissues.

4. Your drawing should cover more than the half of the space given.


When labelling(if you are asked to do so….)

1. label using a pencill and make sure the end of the line exactly touches the structure.

2. write the labels horizontally and outside the drawing itself.

3. Don't cross over the lines when labelling.

A. Cell Structure (1)

 [PA] use an eyepiece graticule and stage micrometer scale to measure cells and be familiar with units (millimeter, micrometer, nanometer) used in cell studies; Calibration with a standard stage micrometer with pitch [0.1 mm]

(2) [PA] compare and contrast the structure of typical animal and plant cells;

Characteristics and roles;

Root and Stem:

 ▪ Epidermis: surface of the stem made of a number of layers often with a waxy cuticle to reduce water loss.

Cortex Tissue:

 Forming a cylinder of tissue around the outer edge of the stem. Often contains cells with secondary thickening in the cell walls which provides additional support.

Vascular bundle:

 contains xylem, phloem and cambium tissue. ▪ Xylem: a longitudinal set of tubes that conduct water and mineral salts from the roots upward

Spongy mesophyll: 

contains spaces that allows the movement of gases and water through the leaf tissue..

Lower epidermis: 

bottom surface layer of tissues which contains the guard cells that form each stoma

(4) [PA] calculate linear magnification of drawings and photographs; m = (I/O) [I measured with a 30 cm rule and O with a calibrated eyepiece graticule] 

(5) [PA] calculate the actual sizes of specimens from drawings and photographs