What is heat?
Heat is the transfer of thermal energy between two objects due to a temperature difference.
What is temperature?
Temperature is a measure of the average kinetic energy (particle agitation) of particles in a substance.
In what direction does heat always flow?
From the hotter object to the cooler object.
What is a closed system?
A system that can exchange energy but not matter with its surroundings. a mug of coffee with lid
What is an open system? and exemple
A system that can exchange both matter and energy with its surroundings. mug of coffee
Why is a calorimeter considered an isolated system?
Because it is insulated, preventing heat exchange with the surroundings.
What is an isolated system?
A system that exchanges neither matter nor energy with its surroundings.
What is a calorimeter used for?
Measuring heat transfer during physical or chemical changes.
If the temperature of the water in a calorimeter increases, what happened?
The reaction released heat (exothermic).
If the temperature of the water decreases, what happened?
The reaction absorbed heat (endothermic).
What is specific heat capacity?
The amount of energy required to raise the temperature of 1 g of a substance by 1°C.
c of water
4.184 J/(g·°C)
What does a negative Q value mean?
Heat was released by the system.
What does −Qloss = Qgain mean?
Heat lost by one substance equals heat gained by another in an isolated system.
Why must the system be isolated for this equation to work?
To ensure no heat escapes to the surroundings.
What happens to two objects exchanging heat in an isolated system?
They reach the same final temperature.
Where will the final temperature be relative to initial temperatures?
Between the two initial temperatures.
formula for solving for final temperature (Tf)
Tf= m2c2Ti2+m1c1Ti1/m1c1+m2c2
What is enthalpy change (ΔH)?
The energy exchanged between a system and surroundings at constant pressure.
What does a negative ΔH indicate?
An exothermic reaction.
What does a positive ΔH indicate?
An endothermic reaction.
formula for enthalpy change
ΔH= Hp(products)-Hr(reactants)
How do products compare to reactants in an exothermic reaction?
Products have lower enthalpy than reactants.
How do products compare to reactants in an endothermic reaction?
Products have higher enthalpy than reactants.
