Chemistry, 02.10.2019 16:30, danielleepham

Lily replicates an experiment that found that the number of calories in a particular food is 50 kcal. she obtained data from

five trials: 50 kcal 72 kcal, 50 kcal, 12 kcal, and 50 kcal. which best desribes her data results? a. accurate b. incorrect c. invalid d. precise

Answers: 3

Show answers

Answers

answered: aletadaboss

Option A. accurate.

Explanation:

Accuracy describes how close the experimental measure is to the correct value.

In this case the number of calories found in the experiment that is being replicated would be considered as the correct value to compare: 50 kcal.

The result of the experiment carried out by Lily is the average of the five trials:

Average = ∑ measures / amount of measuresAverage = [50 kcal + 72 kcal + 50 kcal + 12 kcal + 50 kcal] / 5 = Average = 234 kcal /5 = 46.8 kcal

Round to two significant figures:

Average = 47 kcal

Find the error:

Error = | correct value - obtained value | / (correct value) × 100 = Error = [50 kcal - 47 kcal] / 50 kcal × 100 = 6%

That is not a big error, that drives to conclude that the data results are incorrect, so discard option B (incorrect) and it is, indeed, relatively accurate.

Precision measures how close the data obtained are close to each other. You can see that there is great dispersion, since the data are in the range [12, 72], which is too big compared with the average.

Thus, at once you can conclude that the data are not precise (option D. is discarded).

You cannot talk about validity since that is more related with the experimental procedure, so discard option C.(invalid).

answered: Guest

answer : (a) volume of the gas = 8.67 × $10^{-3}$ l

(b) second virial coefficient b = -1.21226 l/mole

solution : given, t = 300k

p = 20atm

z = 0.86

n = 8.2 mmoles = 8.2 × $10^{-3}$ moles

r = 0.082 l atm/k/mol

find, (a) volume of gas and (b) second virial coefficient b at 300k.

formula used : $z=\frac{pv}{nrt}$

and $z=1+\frac{b}{v}$

(a) $z=\frac{pv}{nrt}$

$v=\frac{znrt}{p}$

= $\frac{0.86\times 8.2\times[tex]10^{-3}$ \times 0.082\times 300}{20}[/tex]

= 8.67 × $10^{-3}$ l

(b) $z=1+\frac{b}{v}$

$b=(z-1)v$

= (0.00867-1) × 8.659

= - 8.5839 l/mole

answered: Guest

The answer is accuracy

Other questions on the subject: Chemistry

Chemistry, 22.06.2019 06:00, joelpimentel

This flow chart shows the amount of energy that is emitted by each type of light. ultraviolet > blue light > yellow light > red light (maximum energy) (minimum energy) in an experiment, shining which type of light on a strip of metal would be least likely to produce the photoelectric effect? ultraviolet light dim blue light bright red light bright yellow light

Answers: 2

continue

Chemistry, 22.06.2019 10:10, alvaradolm6853

What shape would a molecule with two bound groups and two lone pairs have?

Answers: 1

continue

Chemistry, 22.06.2019 11:10, hannah2757

Which of the following shapes would represent a molecule with two bonded atoms and 3 lone pairs on only one of them , trigonal planar , bent , trigonal pyramidal , linear

Answers: 1

continue

Chemistry, 22.06.2019 14:30, malenacastillo4887

For the reaction shown, find the limiting reactant for each of the following initial amounts of reactants. 4al(s)+3o2(g)→2al2o3(s) a) 1 molal, 1 mol o2 b) 4 molal, 2.6 mol o2 c) 16 molal, 13 mol o2 d) 7.4 molal, 6.5 mol o2

Answers: 3

continue

Do you know the correct answer?

Lily replicates an experiment that found that the number of calories in a particular food is 50 kcal...