Chapter 3 Review Flashcards
What is a temperature-time curve?
This is a graph of the relationship between time and the temperature of a substance. Time = x-axis, temp. = y-axis
What is the difference between boiling and evaporation?
Boiling - there is a chemical definition
Evaporating - the molecules “jumping” out of the water
How do you show that particles are vibrating in a particle diagram?
parentheses
In a temperature-time curve, how can you tell which form of energy is being absorbed or released?
Flat is Eph
What is an exothermic reaction?
Where energy is released to the surroundings
What is an endothermic reaction?
Where energy is absorbed from the surroundings
What does phase energy go to do?
The energy is spent breaking bonds
How do you assign values to Eph in an energy bar chart?
Solids = 1 bar, liquids = 2 bars, gasses = 4 bars
How do you assign values to Eth in energy bar charts?
It needs to be consistent
If a questions asks about energy being absorbed by ice of 2/3 of it is melted, what do you do the equation?
Multiply the answer by 2/3 to get the actual Q value
What is the difference between Cal, kcal, and cal?
Cal and kcal are 1000 cal
As a substance gets hotter or colder or changes phase, what happens to energy?
It is transferred either into or or out of the system
What are the two key ways that energy is stored?
Thermal or phase energy
How is energy stored thermally?
Through the motion of the particles
How is energy stored through phases?
Through the attractions between particles
What do attractions to the energy state?
They lower it
To pull the particles apart, what must one do?
Add energy to the system
What are the 3 ways that energy is transferred?
Heating (Q), working (W), and radiating (R)
What is kinetic molecular theory?
All matter is composed of tiny particles in endless random motion. In solids, they vibrate and are locked in an orderly array. In liquids, they are still touching, but are free to move around each other. In a gas, they are moving very rapidly and are widely separated.
When energy is transferred to a sample of matter, what two things can happen?
The particles speed up (temp. increases) or they get pulled apart (phase change. NEVER AT THE SAME TIME
When energy is transferred to a sample of matter, what is unique about the 2 possibilities?
They are mutually exclusive –> they cannot happen at the same time
how does the two possibilities shape the warming curve?
Since while the particles are being pulled apart there is no temperature increase, there is a flat line here.
When the temperature of a solid, liquid, or gas is changing, what does energy have to do with this?
There is energy transfer via heating (Q)
When a substance is undergoing phase change, which constant is used?
Hf for melting or freezing and Hv for evaporating or condensing
