enalphy

Question 1

enathalpy notation

Answer 1

delta h

Question 2

delta h units

Answer 2

kj mol-1

Question 3

enthalphy change definitation

Answer 3

the heat change in standards conditions. pressure at 100kpa and temperatures of 298k.

Question 4

exothermic reactions

Answer 4

energy is released to the surrounding of the chemical reaction. this is breaking bonds. the new bonds has less energy than the old bonds combined.

negative sign

Question 5

endothermic reaction

Answer 5

energy is absorbed by the surrounding for the reaction to take place. the temperature of the reaction falls. This is breaking bonds.

Question 6

what are bond enthalphy

Answer 6

atoms in molecules are held be strong covalent bonds, it takes energy to break bonds and energy is released in making bonds.

Bond enthalphy is the energy to break bonds

Question 7

making bonds

Answer 7

negative h
stronger bonds release more energy when made.
stronger bonds require more energy

Question 8

breaking water

Answer 8

h-oh = 492kj
h-o = 428
the second one has is easier to break apart since it has extra electron replusion

Question 9

The standard molar enthalpy of formation.

Answer 9

is the enthalpy change when one mole of substance is formed from its constituent elements under standard conditions which is temperatures of 298k and pressures of 100kpa. all reactants and products being in their standard states.

Question 10

The standard molar enthalpy of combustion,

Answer 10

is the enthalpy change when one mole of substance is completely burnt in oxygen under standard conditions which is temperatures of 298k and pressures of 100kpa, all reactants and products being in their standard states.

Question 11

how to measure temperature

Answer 11

Temperature is measured with a thermometer silly billy

Question 12

temperature is the

Answer 12

average kinetic energy of the particles in a system. As the particles move faster, their average kinetic energy increases and the temperature goes up.

Question 13

temperature is independent to what

Answer 13

But it doesn’t matter how many particles there are. temperature is independent of the number present.

Question 14

Heat is a measure of the

Answer 14

total energy of all the particles present in a given amount of substance.

Question 15

heat depends on

Answer 15

on how much of the substance is present. The energy of every particle is included.

Question 16

case study example of heat vs temperature

Answer 16

So a bath of lukewarm water has much more heat than a red hot nail because there arc so many more particles in it. Heat always flows from high to low temperature, so heat will flow from the nail into the bath water.
even though the water has much more heal than the nail.

Question 17

heat flows from

Answer 17

Heat always flows from high to

low temperature

Question 18

how to measure enthaply change

Answer 18

1 mass of the substance that is being heated up or cooled down
2 temperature change
3 specific heat capacity of the substance.

Question 19

specific heat capacity

Answer 19

The specific heat capacity c is the amount or heat needed to raise
the temperature of Jg of substance by I K.