1 / 6

Understanding Energy Changes in a Substance: Thermodynamics and Heat Calculations

This unit explores the fundamental concepts of thermodynamics related to energy changes in a single substance. It focuses on how energy is transferred in the form of heat, measured in joules (J), and provides insights into specific heat capacity, which is crucial for calculating temperature changes. Utilizing the formula Q = mcΔt, where Q represents energy, m is the mass, c is the specific heat capacity, and Δt is the temperature change, learners will engage with practical examples to explore heat absorption and release in various substances.

osbourne-olsen
Télécharger la présentation

Understanding Energy Changes in a Substance: Thermodynamics and Heat Calculations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Unit 03 - Thermodynamics 02 – Energy Changes in one substance

  2. Calculating Energy Changes in One Substance: • When energy is given off in the form of heat, this value can be measured or calculated • Recall that the base unit for energy is the joule (J) • If the amount of heat given off by a substance is to be measured, its specific heat capacity must also be known. • Specific heat capacity is defined as the amount of heat required to raise 1 g of a substance 1˚C. Therefore the units for a substance’s specific heat capacity is J/g˚C. • The specific heats of several substances will be provided for you (Page 42 in your text has a few)

  3. Calculating Energy Changes: • There is a WAY COOL FORMULA we can use to calculate the amount of energy absorbed or released from a substance when the temperature changes. It is: Q = mc∆t • Q = energy (J) absorbed or released • m = mass of the substance (g) • c = specific heat capacity (J/g°C) • ∆t = change in temperature (°C) • tfinal - tinitial

  4. Calculating Energy Changes: • Please note: • When using the Q = mc∆t formula: • If heat is absorbed, Q will be positive. • If heat is released, Q will be negative. • The value of Q itself will always be positive. You need to understand mentally if Q is representing heat being absorbed or heat energy being released; the negative sign is simply representing if it’s absorbed or released

  5. Example 1: • What quantity of heat is required to raise the temperature of 100.g of liquid water 10.°C?

  6. Example 2: • What quantity of heat is released when 420.0g of lead cools from 85°C to 25°C? The specific heat capacity of lead is 0.13J/g°C.

More Related