Logout Open In App
Open In App
Warning: foreach() argument must be of type array|object, bool given in /var/www/html/web/app/themes/studypress-core-theme/template-parts/header/mobile-offcanvas.php on line 20

Chapter 9: Q10DQ (page 343)

In the equation w = - PΔV, why is there a negative sign?

Short Answer

Expert verified

Negative sign in the equation w=−PΔVindicates work is done by the system or the flow of work from system to surroundings.

Step by step solution

01

Definition of work

Work is defined as the force applied over a distance.

02

Reason for the negative sign in the equation w = - PΔV.

At constant pressure, volume of the gas expands which results in rise in moving piston against the pressure which holds it in place. The system is doing work on the surroundings. The sign here is negative w=−PΔV for work done whichindicates that work is done by the system or the flow of work from system to surroundings.

If the volume of the system decreases, it results in positive sign of work done and here the wok is applied on the system.

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

When 1.00 L of 2.00 M Na2SO4 solution at 30.00C is added to 2.00 L of 0.750 MBa (NO3)2 solution at 30.00C in a calorimeter, a white solid (BaSO4) form. The temperature of the mixture increases to 42.00C. Assuming that the specific heat capacity of the solution is 6.37 J 0C-1 g-1 and that the density of the final solution is 2.00 g/mL, calculate the enthalpy change per mole of BaSO4 formed.

The specific heat capacity of silver is 0.24J/°Cg

  1. Calculate the energy required to raise the temperature of 150.0 g Ag from 273 K to 298 K.
  2. Calculate the energy required to raise the temperature of 1.0 mole of Ag by1.0°C (called the molar heat capacity of silver).
  3. It takes 1.25 kJ of energy to heat a sample of pure Silver from12.0°C to 15.0°C. Calculate the mass of the sample of silver.

Question: Calculate ∆H for the reaction

2NH3(g) + O2(g) ----> N2H4(l) + H2O(l)

given the following data:

2NH3 (g) + 3N2O(g)---> 4N2(g) + 3H2O(l) ∆H = -1010 kJ

N2O(g) + 3H2 g) ---> 2N2H4 (l)+ H2O(l) ∆H = -317 kJ

N2H4(l) + O2(g) ---> N2 (g) + 2H2O(l). ∆H= - 623 kJ

H2(g) + O2 (g) ---> H2O(l) ∆H = - 286 kJ

Predict the signs of q and w for the process of boiling water.

The heat capacity of a bomb calorimeter was determined by burning 6.79 g of methaneenergyofcombustion=-802kJ/molCH4 in the bomb. The temperature changed by 10.80C.

a. What is the heat capacity of the bomb?

b. A 12.6g sample of acetyleneC2H2 produced a temperature increase of16.90C in the same calorimeter. What is the energy of combustion of acetylene inkJ/mol?
See all solutions

Recommended explanations on Chemistry Textbooks

Ionic and Molecular Compounds

Read Explanation

Chemical Reactions

Read Explanation

Chemistry Branches

Read Explanation

Inorganic Chemistry

Read Explanation

Chemical Analysis

Read Explanation

Physical Chemistry

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