THERMOCHEMICAL CHANGES 1

QUIZ 1

enthalpy change

basis of all change is due to energy transformations, sum of all eK + eP

what takes solar energy from the sun and transforms it to _______ of glucose which in turn is transformed by…

photosynthesis

chemical energy

living things to thermal energy and mechanical energy of movement

what is a stored form of chemical energy in which its origin can be traced back to the solar energy of the sun?

fossil fuels

is cell resp exo or endo?

exo

is photosyn exo or endo?

endo

what occurs in the body, cell resp or photosyn

cell resp

what occurs in plants, cell resp or photosyn

photosyn

examples of exothermic changes

combustion, hot packs, cell resp

examples of endothermic changes

cold pack, photosyn, evaporation, perspiration

What is the Law of conservation of energy

energy cannot be created or destroyed

energy can be changed or converted from one form or another

What is the Law of heat exchange or transfer?

heat energy flows ( moves ) from a hot to a cold object until thermal equilibrium is reached ( both are at the same final temperature )

total heat lost equals..

total heat gained

what is thermochemistry

the study of energy changes during a chem reaction

what requires to be working in an isolated system

thermochemistry

whats an isolated system

no matter or energy exchange

energy gained by the chemical system is equal to what

the energy lost by the calorimeter and its contents, as long as both the calorimeter and its contents ( surroundings ) are part of an isolated system

what is the main assumption when using a calorimeter

no heat is transferred to the outside of the calorimeter

kinetic molecular theory

smallest particles of any substance are in continuous motion

what is released when collisions occur

energy

energy of motion is given what name

kinetic energy

what happens if there is enough energy produced upon collision?

reaction or change will take place

temperature of a substance is a measure of the average…

kinetic energy of the particles of the substance

substances at the same temp are believed to have particles with..

the same average kinetic energy

if what of the reactants and products are the same what does it indicate?

temp

no change in eK of the system

if temperature is kept constant, then the only change of enthalpy is the result of a change in…

eP

what is enthalpy change

difference between the enthalpy of the products and the enthalpy of reactants.

exothermic reaction is represented by a ____ enthalpy change

negative

endothermic reaction is represented by a ____ enthalpy change

positive

whats molar enthalpy of reaction

enthalpy change when one mole of a specified chemical undergoing a change in the system at constant pressure

what are the four methods of communicating enthalpies

molar enthalpy

enthalpy changes for 4 moles of the substance

balance thermochemical equation for 4 moles

ep diagram for 4 moles

what does ep diagram represent

it shows change in ep during a chem reaction

Cell resp equation

C6H12O6+6O2→6CO2+6H2O+2802.7KJ

Photosyn equation

6CO2+6H2O+2802.7KJ→C6H12O6+6O2