Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 3: Q13P (page 62)

Cheryl, Cynthia, Carmen, and Chastity shot the following targets at Girl Scout camp. Match each target with the proper description.

(a) accurate and precise

(b) accurate but not precise

(c) precise but not accurate

(d) neither precise nor accurate

Short Answer

Expert verified

A. The points in Carmen's goal are close together (just in the innermost circle) and match the target (only in the inner circle). As a result, it's precise and precise.

B. Although the points in Cynthia's aim are not close to each other (in the innermost circle and beyond), they do agree on the goal in other respects (only in the innermost circle and the next). As a result, it's accurate but not precise.

C. Chastityl's target has points that are close together but not in line with the target (near the outer boundary). As a result, it's accurate but not precise.

D. The points in Cheryl's goal aren't close to each other (they're strewn throughout the place).

Step by step solution

01

Definition of systematic and random error.

  • Systematic errors are mistakes that are not caused by chance, but rather by an inherent inaccuracy in the system (including either the observation or measurement process). The term "systematic error" can also refer to a mistake with a nonzero mean that has no impact when the observations are averaged.
  • The term "random error" refers to an unanticipated disruption in the experiment caused by an unknown source. In theory, you may track down the cause of the mistake and eliminate it in a better trial, bringing the measured mean closer to the real mean. Random mistake can be either beneficial or harmful, and it can't be avoided.
02

Determine whether the error in (a)-(d) is systematic or random.

  • The points in Carmen's goal are quite near to each other (only in the innermost circle) and agree with the target (only in the inner circle). As a result, it's exact and accurate.
  • The points in Cynthia's target are not near to each other (in the innermost circle and next to that), but they do agree on the goal in other ways (only in the innermost circle and the next). As a result, it is precise but not exact.
  • The points in Chastityl's target are close together but not in accord with the target (near the outer boundary). As a result, it is precise but not exact.
  • The points in Cheryl's objective are neither near to each other (scattered throughout the chart) nor in accord with the target (only one at the innermost circle). As a result, it is neither exact nor precise.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

You have a stock solution certified by a manufacturer to contain 150.0±0.3μgSO42-/mL. You would like to dilute it by a factor of 100 to obtain 1.500μg/mL. Two possible methods of dilution are stated below. For each method, calculate the resulting uncertainty in concentration. Use manufacturer's tolerances in Tables 2-3 and 2-4 for uncertainties. Explain why one method is more precise than the other.

(a) Dilute 10.00mL up to 100mL with a transfer pipet and volumetric flask. Then take 10.00mL of the dilute solution and dilute it again to 100mL.

(b) Dilute 1.000mL up to 100mL with a transfer pipet and volumetric flask.

Explain the difference between systematic and random error.

Find the absolute and percent relative uncertainty and express each answer with a reasonable number of significant figures.

a)6.2±0.2-4.1±0.1=?b)9.43±0.05×0.0160.001=?c)6.2±0.2-4.1±0.1÷9.43±0.05=?d)9.43±0.05×6.2±0.2×10-3+4.1±0.1×10-3

We can measure the concentration of HCI solution by reaction with pure sodium carbonate: 2H++Na2CO3→2Na++H20+105.9884±0.0007required 27.35±0.04mLof HCI .

(a) Find the formula mass (and its uncertainty) for Na2CO3.

(b) Find the molarity of the HCI and its absolute uncertainty.

(c) The purity of primary standard Na2CO3is stated to be 99.95 to 100.5wt % , which means that it can react with (100.00±0.05)%of the theoretical amount of H+. Recalculate your answer to (b) with this additional uncertainty.

Avogadro's number can be computed from the following measured properties of pure crystalline silicon: 5

(1) atomic mass (obtained from the mass and abundance of each isotope), (2) density of the crystal, (3) size of the unit cell (the smallest repeating unit in the crystal), and (4) number of atoms in the unit cell. For the material that was used, the average atomic mass of Si is role="math" localid="1663313481329" msi=28.0853842(35)g/mol, where 35 is the uncertainty (standard deviation) in the last two digits. The density is p=2.3290319(18)g/cm3, the size of the cubic unit cell is c0=5.43102036(33)×10-8cm, and there are 8 atoms per unit cell. Avogadro's number is computed from the equation

NA=mSi(pc03)/8

From the measured properties and their uncertainties, compute Avogadro's number and its uncertainty.

To find the uncertainty of con3 use the function y=x4in Table 3-1.
See all solutions

Recommended explanations on Chemistry Textbooks

The Earths Atmosphere

Read Explanation

Organic Chemistry

Read Explanation

Making Measurements

Read Explanation

Chemical Analysis

Read Explanation

Chemical Reactions

Read Explanation

Ionic and Molecular Compounds

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free