Energy Flashcards
(23 cards)
What is energy according to the Principle of Conservation of Energy?
Energy can neither be created nor destroyed but it can be changed from one form to another.
We measure the energy changes denoted by the greek letter….
triangle
Reactions can be of two types.
Exothermic and endothermic
Exothermic reactions
Are those reactions which upon reaction of reactants(is the substance that is taking part in the experiment) form products and liberate heat energy.
What is thermal energy?
Thermal energy is the energy generated and measured by heat
Upon Exothermic reaction what type of energy is released?
Thermal energy
Upon exothermic reaction, thermal energy is released and thus the products are found at a…………. energy.
lower
Mention examples of exothermic reaction.
reaction between H and O= H20
reaction between C and O=CO2
reaction between ethene and H= ethane
Reaction of exothermic energy have a (negative of positive)? (see graph)
negative because the products have a less amount of energy than the reactants.
What is endothermic reaction? (See graph)
Endothermic reaction is a reaction in which the reactants gain energy in the form of heat thus the products are at a higher energy than the reactants.
Reactions of endothermic have a (positive or negative)?
Positive
Examples of endothermic include the reactions between….
non-metals ex: formation of carbon disulphide
A mole is defined as
6.02214076 × 10 23
What is the heat of combustion?
it is the heat change taking place when 1 mole of substance is completely burnt in air. example C+O2–> CO2 in this reaction only one mole of C is burned in the air to produce CO2.
What is the heat change of solution?
Is the heat taking place when 1 mole of a substance is completely dissolved in the solvent. See equation of sodium with water.
What is the heat change of neutralisation?
Is the heat change taking place when an acid and a base react together to form one mole of water.
Acid+base–>one mole of water (see example of sodium hydroxide + HCL
What is the heat change of precipitation?
Is the heat change taking place when 1 mole of a substance is precipitated during a precipitation reaction. (see example of KBr+AgNO3–> KNO3+AgBr
What is reaction?
Is the heat taking place when a reaction takes place between the number of moles indicated in the equivalent balanced equation.
Endothermic reactions are those involving bond……
breaking
Exothermic reactions are those involving bond…..
making
In endothermic the energy needed to break bonds is ……..
greater than energy needed to make bonds
In exothermic the energy needed is ……
more greater to make bonds than to break bonds.
What is calorimetry?
Set of experiments to determine the energy heat change of a reaction.
