Chapter 14 - Energy changes in chemical reactions Flashcards
What are exothermic reactions?
Reactions that release heat.
What are endothermic reactions?
Reactions that absorb heat
What is thermochemistry?
The study of energy changes in chemical reactions.
What is temperature?
The physical quantity we use to measure the degree of hotness or coldness of an object or substance.
What does specific heat capacity of a substance mean?
The amount of heat required to increase the temperature of unit mass of the substance by exactly 1C.
What is calorimetry?
The measurement and calculation of heat changes.
What formula is used to calculate the quantity of heat absorbed/released?
q=mc∆T
What does ∆T mean?
The change in temperature.
What does q mean in the q=mc∆T formula?
Quantity of heat absorbed.
How do we calculate heat released/absorbed per mole?
total heat release or absorbed/number of moles that reacted
What is enthalpy?
A measure of the total energy possessed by a substance or group of substances.
When a reaction is exothermic is ∆H positive or negative?
Negative.
What does c mean in the q=mc∆T formula?
The specific heat capacity.
What is the change in enthalpy for a chemical reaction ∆H mean?
The heat absorbed per mole of specified reactant or product when the reaction occurs at constant pressure.
When a reaction is endothermic is ∆H positive or negative?
Positive.