Energy – the ability to do work or produce Potential energy



Download 124.62 Kb.
Page1/4
Date13.08.2021
Size124.62 Kb.
#93735
  1   2   3   4

Energy

Energy


Energy – the ability to do work or produce ______

Potential energyenergy due to _____________ of an object

Kinetic energy – the energy of motion

Energy


The SI unit for energy is the ____________

1 J = 1 Kgm2 / s2

Another unit of energy that you may be more familiar with is the calorie

calorie – amount of energy required to raise _____________

1 cal = 4.18 J

1000 calories = 1 Kilocalorie = 1 Calorie

Energy Conversions

Convert 15,500 joules into Calories

Formulas – Kinetic Energy

Kinetic energy

KE = ____________

KE = kinetic energy (joules)

m = mass (must be in Kg)

V = velocity (must be in m/s)
Formulas – Potential Energy

Potential Energy

PE = __________

PE = Potential Energy (J)

m = mass (Kg)

g = gravitational constant = 9.8 m/s2

h = height (m)

Formulas - Work

Work (w) –______________

Force (F) – a push or pull on an object

W = mgd = Fd = PE

Work and potential energy can be looked at in the same light

No distance __________________

Examples


A bowler lifts a 5.4 kg bowling ball 1.6m and then drops it to the ground.

How much work was required to raise the ball?

Examples

How much potential energy does that ball have at this height?


If the ball is dropped and we assume that all of the potential energy is turned into kinetic energy, at what velocity will the bowling ball hit the ground?
More examples

What is the kinetic energy of 1 atom of Ar moving at 650 m/s?

1st Law of Thermodynamics

1st Law of Thermodynamics – energy is conserved

The law of conservation of energy states that in any chemical reaction or physical process, energy can be converted from one form to another, but it is neither ____________________

1st Law of Thermodynamics

Since energy can neither be gained nor lost, the change in E can be calculated using:

DE = Ef – Ei

In a chemical reaction i indicates __________ and f indicated ____________

DE

DE has 3 parts:



A # indicating the _____________

A sign (+/-) indicating the _____________-

A unit

Thermochemistry



Thermochemistry is the study of _______________that accompany chemical reactions and phase changes.

In thermochemistry, the __________ is the specific part of the universe that contains the reaction or process you wish to study.

Thermochemistry

Everything in the universe other than the system is considered the ________________

Therefore, the ____________ is defined as the system plus the surroundings.

Relating D E to heat & work

The system can exchange energy with its surroundings in 2 ways: _________________

DE =_______

DE = change in energy

q = heat


w = work

q & w


Don’t forget q & w must have signs

In order to get the sign you must look at the system as a box and the surroundings as everything else

q & w

Anything going INTO the box will be ___



Anything going OUT of the box will be ________

Examples


A system absorbs 140 J of heat from the surroundings and does 85 J of work on the surroundings. Calculate D E.

Endothermic & Exothermic





Download 124.62 Kb.

Share with your friends:
  1   2   3   4




The database is protected by copyright ©essaydocs.org 2022
send message

    Main page