Error Of 10cm3 Measuring Cylinder
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error'). Experimental uncertainty arises because of: Limits in the how exact the measuring apparatus is. This is the precision of the apparatus. Imperfections in experimental procedures. Judgements made by the operator. When
250cm3 Measuring Cylinder Uncertainty
can my results be said to be precise? If you repeat a measurement several times percentage error of equipment and obtain values that are close together, your results are said to be precise. If the same person obtains these close values, 25cm3 measuring cylinder then the experimental procedure is repeatable. If a number of different people carry out the same measuring procedure and the values are close the procedure is reproducible. What is a systematic error? A systematic error is
Percentage Error Of Burette
one that is repeated in each measurement taken. If this is realised after the experimental work is done, it can be taken into account in any calculations. What are random errors? Even the most careful and experienced operator cannot avoid random errors. However, their effect can be reduced by carrying out a measurement many times (if the opportunity exists) and working out an average value. Let's look in more detail at 'built-in' uncertainty
100 Cm3 Measuring Cylinder Uncertainty
of some laboratory equipment... Some measurement uncertainties are given below: EquipmentMeasurement to the nearest: Balance (1 decimal place)0.08 g Balance (2 decimal place)0.008 g Balance (3 decimal place)0.0008 g Measuring Cylinder (25 cm3)0.5 cm3 Graduated Pipette (25 cm3, Grade B)0.04 cm3 Burette (50 cm3, Grade B)0.08 cm3 Volumetric Flask (250 cm3, Grade B)0.2 cm3 Stopwatch (digital)0.01 s Calculating the percentage uncertainty (often called percentage error) ... Now try calculating the following percentage uncertainties... 1.00 g on a 2 decimal place balance 10.00 g on a 2 decimal place balance 1.00 g on a 3 decimal place balance 10 cm3 in a 25 cm3 measuring cylinder 25 cm3 in a 25 cm3 measuring cylinder 25 cm3 in a 25 cm3 graduated pipette (Grade B) 25 cm3 in a 50 cm3 burette (Grade B) 250 cm3 in a 250 cm3 volumetric flask (Grade B) 50 s on a digital stopwatch 8% 0.8% 0.08% 5% 2% 0.16% 0.32% 0.08% 0.02% Comparing uncertainties like those calculated above 'might' help you to decide which stage in an experimental procedure is likely to contribute most to the overall experimental uncertainty. How about thermometers...? Spirit filled thermometers are regularly used in college laboratories. They are often more precise than accurate. It is quite easy to read a thermometer to the nearest 0.2 °C. However, t
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10cm3 Pipette Error
by Contributing Earn Free AccessLearn More > Upload Documents Write Course Advice Refer your Friends Earn MoneyLearn More > Upload Documents Apply uncertainty of pipette for Scholarship Create Q&A pairs Become a Tutor Are you an educator? Log in Sign up Home Cambridge CHEMISTRY CHEMISTRY 9701 9701_s11_qp_34 Using a 25 cm 3 measuring cylinder add about 10 cm 3 SCHOOL http://www.avogadro.co.uk/miscellany/errors.htm Cambridge COURSE TITLE CHEMISTRY 9701 TYPE Test Prep UPLOADED BY RitwikP PAGES 12 Click to edit the document details This preview shows pages 3–7. Sign up to view the full content. View Full Document Using a 25 cm 3 measuring cylinder, add about 10 cm 3 of FB 4 . • Using the same measuring cylinder, add about 10 cm 3 of FB 5 . • Titrate the mixture in the https://www.coursehero.com/file/p7an8l1/Using-a-25-cm-3-measuring-cylinder-add-about-10-cm-3-of-FB-4-Using-the-same/ flask with FB 2 until the colour is pale yellow. • Add about 10 drops of starch indicator. A blue-black colour should be seen as the starch reacts with the remaining iodine. • Continue to add FB 2 until the blue-black colour just disappears leaving a colourless solution. You should perform a rough titration . In the space below record your burette readings for this rough titration. The rough titre is ……………… cm 3 . • Carry out as many accurate titrations as you think necessary to obtain consistent results. • Make certain any recorded results show the precision of your practical work. • Record in an appropriate form below all of your burette readings and the volume of FB 2 added in each accurate titration. [7] (b) From your accurate titration results obtain a suitable value to be used in your calculations. Show clearly how you have obtained this value. The iodine produced by 25.0 cm 3 of FB 3 required ……………… cm 3 of FB 2 . [1] I II III IV V VI VII This preview has intentionally blurred sections. Sign up to view the full version. View Full Document 4 9701/34/M/J/11 © UCLES 2011 For Examiner’s Use (c) Calculations Show your working and appropriate significant figures in the
Solutions 1. Approximations If a quantity x (eg, side of a square) is obtained by measurement and a quantity y (eg, area of the square) is calculated as a function of x, say y = http://www.phengkimving.com/calc_of_one_real_var/08_app_of_the_der_part_2/08_04_approx_of_err_in_measrmnt.htm f(x), then any error involved in the measurement of x produces an error in the calculated value of y as well. Recall from Section 4.3 Part 2 that the Section 8.3 Part 1, we have: That is, the error in x is dx and the corresponding approximate error in y is dy = f '(x) dx. Fig. 1.1 Fig. 1.2 – 1st and 2nd axes: if measuring cylinder 1,000 = xa – 1 then xa = 1,001, – 1st and 3rd axes: if 1,000 = xa + 1 then xa = 999, therefore xa is somewhere in [999, 1,001]. Example 1.1 Solution Let s be the side and A the area of the square. Then A = s2. The error of the side is ds = 1 m. The approximate error of the calculated area is: dA cm3 measuring cylinder = 2s ds = 2(1,000)(1) = 2,000 m2. EOS Note that we calculate dA from the equation A = s2, since the values of s and ds are given. To find the differential of A we must have an equation relating A to s. So even if the measured value of the side is given we still define the variable s that takes on as a value the measured value. In general, when the measured value say V of a quantity and the error say E in the measurement are given, we define a variable say x for the quantity, so that x = V and dx = E, which will be used later on in the solution. When using the quantity, first use the variable x, not the value V, then use the value V when a value is to be obtained. Go To Problems & Solutions Return To Top Of Page 2. Types Of Errors A measurement of distance d1 yields d1 = 100 m with an error of 1 m. A measurement of distance d2 yields d2 = 1,000 m with an error of 1 m. Both measurements have the same absolute error of 1 m. However, intuitively we feel that measurement of d2 has a smaller error because it's 10 times larger and yet has the same absolute error. Clearly the effect of
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