how do i find the PERCENT ERROR?

Answer 1

Here's the formula I learned in Chemistry.

|true value - observed value| / true value

I hope you can understand all the crazy symbols.

Answer 2

singinandsmilin has the right idea, but forgot to convert to percent. here's the formula using punctuation that is perhaps more common:

absolute value of [100 x ((Vt - Vo) / Vt)]

Where:

"x" indicates multiplication (read "times" or "multipled by")

Vt = the theoretical "true" or "ideal" value, and

Vo = the observed value

Make sure the units are the same, and perform the subtraction operation (the "inside" parentheses) FIRST. Otherwise, you'll get the wrong answer.

You have to multiply by 100 in order to convert to percent; otherwise, you've only calculated the error fraction.

Finally, remember that percent error does not have a positive or negative sign attached to it: it is expressed in terms of the absolute value of the error (which, I think, is why singinandsmilin used the "|" symbol instead of parenthesis).

Only in the calculation of percent error it doesn't matter mathematically, if you convert to absolute value after the first step or if you wait until sometime later -- as long as you do it.

However, waiting until later can cause you some problems in other calculations. Here's a couple of examples:

Formula: 2 H2 + O2 ----> 2 H2O
H = 1.0078 g/m
O = 15.9994 g/m

Experiment 1:

4.0312 g of hydrogen gas and 31.9988 g of oxygen gas are combusted; 35.8000 g of water is collected as the result. Knowing that 36.0300 g of water ought to have been produced, what is the percent error?

Ignoring "significant" zeros beyond the last non-zero position:

A. (36.03-35.8) = 0.23 absolute error, expressed in grams
B. (0.23/36.03) = 0.006384 error fraction
C. 100 x 0.006384 = 0.638 percent error

Experiment 2:

5.0390 g of hydrogen gas and 39.9985 g of oxygen gas are combusted; 46.1375 g of water is collected as the result. Knowing that 45.0375 g of water ought to have been produced, what is the percent error?

Ignoring "significant" zeros beyond the last non-zero position:

A. (45.0375-48.1375) = 1.1 absolute error, expressed in grams
Again ignoring significant digits, note that the absolute error is not expressed as "-1.1 g," but rather as "1.1 g" (because there are no "negative grams" of matter).

B. (1.1/45.0375) = 0.02442 error fraction
C. 100 x 0.02442 = 2.442 percent error

Answer 3

percentage error .use this as an example.

length is (200cm +/- 4cm)

the percentage error would be 4/200 =0.02
then take 0.02 and multiply by 100 and u get an error of 2%

so ur answer is (200cm +/- 2%)

Answer 4

Suppose you measure a length of 2.00 m
There is an uncertainly of 6 mm.
6 mm / 2.00 m = 6 mm / 2000 mm = 0.3 /100 = 0.3%.
So the error is 0.3% in this case.

Answer 5

search on google.

Answer 6

You get naked, run into a building and shoot yourself

Answer 7

Of what?