Unit 1 Heat and Thermochemistry Flashcards
solid:
liquid:
gas:
particles are tight in a pattern with a definite volume and shape
particle are loosely packed, they move past one another; definite volume, takes shape of container
particles are apart and move around a lot; indefinite shape and takes shape of container and can be compressed
Element:
compound:
mixture:
made of one atom
chemical substance made of 2 or more elements; are chemically combined so has different properties than elements
two or more elements that are not chemically combined
physical property:
chemical property:
can be observed/measured without changing the identity of the substance; is reversible
how matter reacts when a chemical change happens
Temperature:
when particles move apart ________ increases.
average kinetic energy of particles, potential energy increases
Thermal energy:
if either _______ or _______ increases, the thermal energy increases.
the sum of all of the energy in a substance (total energy) ; including kinetic and potential, kinetic, potential
_________ influences thermal energy. Objects can have the same temperature but different thermal energy due to ——–.
mass
Heat:
This is in the unit of Joules
thermal energy that flows from high temperature to low temperature.
heat flows from _______ to _________ until the temperatures are ________ or in _________.
high, low, equal, thermal equilibrium
specific heat:
this varies depending on the ___________.
the amount of heat needed to raise temp of unit mass by 1 C, substance
High specific heat:
Low specific heat:
take more energy to raise OR lower the temperature
takes less energy
What is the formula for calculating temperature change?
q = mcdeltat
If heat is released then q is ________ if absorbed then q is ________.
negative, positive
For the same mass of a substance, molecules of _________ have more thermal energy and higher temp than _________. and has more than _________.
gas, liquid, solid
What is the final temperature?
1. same mass and same specific heat
2. same mass and different specific heat
3. different mass and same specific heat
- exactly halfway
- closer to the initial temperature of the higher specific heat
- closer to the substance with a higher mass
A cooling curve is _______________. A heating curve is __________.
the ________ shows the phase that it is in. changes in _________ Use: _____
________ shows the phase change were there is NO ________. Use: _________
during a phase change the energy is working to change the phase.
negative and losing energy, positive and gaining energy, slopes, temperature, q=mct, straight line, temperature change, mhfusion/vaporization
___________ is the study of thermal energy changes that occur in a nearly isolated system
calorimetry
system is ___________
surroundings _________
boundary __________
the item being observed, anything outside the system, layer that separates system and surroundings.
Types of systems:
closed ___________
open ________
isolated ___________
no mass transfer yes energy transfer
yes mass yes energy
no mass no energy
When q is negative the _______ is giving heat to _________ and when q is positive it is the opposite.
system, surrounding
What is the equation for calorimetry?
mct = -mct
exothermic _____________
endothermic ______________
heat exiting, energy released in light or heat, feels warmer
heat is entering, absorbed, feels cold
Activation energy ____________
energy required to break bonds for a chemical reaction to occur, the highest point of the graph
if energy of reactants is greater than products - ___________-
if energy of reactants is less than products ______________.
exothermic, endothermic
look at notes to see graphs.
look
