1Total energy of reactants= total energy of products+ energy _____ or ________.
Lost
Gained
2what is enthalpy?
The energy of a substance that is under constant atmospheric pressure (e.g substance that is in beaker or test tube)
3what is the symbol for enthalpy?
H
4Can the enthalpies of elements and compounds be measured?
What is it that can be measured?
No
The differences in enthlapy changes are measured
5what is the equation that defines enthalpy change?
Change in enthlpy= sum of enthalpies of products- sum of enthalpies of reactants
6What is the progress of reaction for an exothermic reaction
How does this look on the Enthalpy/progress of reaction graph?
The reactans have more engergy than the products
Reactants are on the top/above
Products are on the bottomnderneath
7What is the progress of reaction for an endothermic reaction
How does this look on the Enthalpy/progress of reaction graph?
The reactants have lesser energy than the procucts
Reactants are on the bottomnderneath
Products are on the top/above
8Is an endothermic reaction positive or negative?
Positive
9Is an exothermic reaction positive or negative?
Negative
10What is the first law of thermodynamics?
Energy can neither be created nor destroyed But can be transferred from one form to another
11What unitsa are enthalpy changes measured in?
kilojoules per mole
- KJ mol-1
12whta are the type of systems
open
closed
isolated
13What is an open system?
-during the reaction there is an exchange of of mass and energy
14What is a closed system?
-during the reaction there is and exchange of energy only
15What is a isolated sysyem
-during the reaction there is no exchange
16If energy is tyransferred from the system to the surroundings the reaction is ___________
heat out= exothermic
17If energy is tyransferred from the surroundings to the system the reaction is ___________
heat in= endothermic
18What happens to the temperature in an exothermic reatction?
- the temperature goes up as heat is given out