Percent error formula

Percent error (%E) can also be figured by the formula given below ... 

L3iZ5ZUiEl 2B What is the percent error of your calculation of the water of hydration for MgS04 if the formula for the hydrate is MgS04 7H20 What changes would you make in the procedure to reduce error ... 

The velocity of light in a vacuum is the same for all wavelengths, 2.998 x 108 m/s. The formula above tells us that there is a simple inverse relationship of wavelength and frequency, k = c/v or u = c/k. The velocity of light in the atmosphere is a little slower than in a vacuum however, the drop in velocity is less than 0.1 percent of that in a vacuum, making 2.998 x 108 m/s acceptable for most applications due to the low percent error introduced. Another term is often used, the wave number, v, defined as 1 Ik (or as v/c). The most common unit for wave number is cm-1. 

The accuracy of a measurement can be improved by making replicate measurements and taking the average. All measurements have some inherent uncertainty. But if the uncertainties are random, then half of the measurements should be too big and half too small. The errors will cancel each other out. Accuracy is assessed by calculating the percent error, which is given by the formula ... 

Quite often when you perform an experiment, your results come close to, but do not actually match, a particular value that you are looking for. You will then want to find out how far off the mark your results were that is, the percent error. For example, suppose you know that the accepted value for the boiling point of vanillin is 83°C, but in your experiment you measured it as 85°C. You could say that you were off by two degrees. Instead, you calculate a percent error by using the formula ... 

For a translational Stokes flow past a convex body of revolution of sufficiently smooth shape with symmetry axis parallel to the flow, the error (in percent) in formula (4.10.9) for the mean Sherwood number can be approximately estimated as follows ... 

Your CD has the Table 2.4 spreadsheet, with formulas as indicated in the table. You can substitute specific weights of water in air, obtained from a flask, pipet, or buret, in cell B at the temperature of measurement to obtain the calculated calibration volume at temperature, T, and for 20°C. We describe the use of spreadsheets in Chapter 3. The CD also has a table and figure of the percent error for weight in vacuum as a function of sample density. 

In cases where the absolute value of the readings q varies significantly from point to point, a similar formula can be used to calculate the percent error and applied to all points regardless of magnitude. 

Error Analysis If the hydrate s formula is MgS04 7H20, what is the percent error in your formula for hydrated MgS04 What are the possible sources for the error What procedural changes could you make to reduce the error ... 

The spectra of floppy molecules such as Lij may therefore have different interpretations. For example, the spectra of specific symmetries have been fitted [11] to within a few percent of error by using the simple vibrational normal mode formula... 

Check of assumptions The values of x and y are not much less than 10% of 0.100, which is pressing the 10% limit of error generally allowed in this chapter. Note that, if the five percent rule were to be applied, there would be a great deal more calculation involved due to the necessary use of the quadratic formula. The point is that you need to be aware of how much error is allowed and stick to that limit. 

From the experimental data, determine the empirical formula of copper(II) chloride, and the error in determining the percent of copper. 

The formulas for one shell pass and 2, 4, 6 tube passes are strictly correct for 2 tube passes but may produce a small error for higher multiples. The error is usually less than 1 percent for C less than 0.5 and N less than 3.0. The formulas may overpredict by about 6.5 percent at N = 6.0 and C = 1.0. Further information is given by Kraus and Kern (10). 

If the percent recovery is less than 99.0%, check the condition of the sieves and for possible errors in weighing, and repeat the test. If the percent recovery is not less than 99.0%, calculate the percent retained on each sieve by the formula... 

The error introduced by use of the Wien equation is less than 1 percent when XT < 3000 pm K. The Wien equation has significant practical value in optical pyrometry for T < 4600 K when a red filter (X = 0.65 pm) is employed. The long-wavelength asymptotic approximation for Eq. (5-102) is known as the Rayleigh-Jeans formula, which is accurate to within 1 percent for XT > 778,000 pm-K. The Raleigh-Jeans formula is of limited engineering utility since a blackbody emits over 99.9 percent of its total energy below the value of XT = 53,000 pm-K. 

Although this approximate molecular mass might be in error by as much as 10 percent, it is sufficiently accurate to allow assignment of the molecular formula Si2Hs (molecular mass 62.2) and to rule out SiHa (31.1), SijH9 (93.3), and higher multiples of the empirical formula unit mass. 

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