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Definitions
Hess's Law
q=mc∆t
Exothermic Reaction or Endothermic
Random Facts
100
The matter around a substance that is capable of absorbing or releasing thermal energy.
What is the surroundings?
100
The value of the ∆H for any reaction that can be written in steps equals the sum of the values of ∆H for each of the individual steps.
What is Hess' Law?
100
In the equation q=mc∆t c represents
What is the specific heat constant
100
Releasing of thermal energy as heat flows out of the system.
What is an exothermic reaction?
100
A Swiss-born Russian chemist and physician who created the law that states that the total enthalpy change during the complete course of a reaction is the same whether the reaction is made in one step or in several steps
What is Mr. Germain Hess
200
An energy system that both matter and energy can move in or out.
What is an open system?
200
What is needed to balance the two reactions to match the target reaction: N2 + O2 ---> 2NO 1. 1/2N2 + O2 ---> NO2 2. NO + 1/2O2 ---> NO2
What is multiplication of 2 for the first reaction and multiplication of -2 for the second reaction?
200
The equation q=mc∆t is used to find.
What is the molar enthalpy change in a substance?
200
The following is an example of what reaction. N2 + 3H2 + 453KJ --->2NH3
What is an endothermic reaction?
200
The setting of concrete is a ______ reaction, and the rate at which it sets determines the hardness of the concrete.
What is an exothermic reaction
300
A device in which a fuel is burned inside an insulated container to measure heat transfer during chemical reactions.
What is a bomb calorimeter?
300
Rewrite the equation N2 + 3H2 + 362KJ ---> 2NH3 to show the enthalpy with respect to hydrogen
What is 1/3N2 + H2 + 120.67KJ ---> 2/3NH3
300
A gram of sand is hotter than a gram of water are at the same temperature. When heated by the same temperature will it take the same amount of energy to heat them. Why or why not.
What is the c value or specific heat capacity will vary the amount of energy needed to heat the substances up
300
A graph where the products are lower than the reactants.
What is an exothermic reaction graph?
300
Name 2 ways that chemical systems have many different forms of energy, both kinetic and potential.
Can be any two : • Moving electrons within atoms •Vibration of atoms connected by chemical bonds •Rotation and translation of molecules •The nuclear potential energy of protons and nuetrons •the electronic potential energy of atoms connected by chemical bonds
400
The enthalpy change associated with a physical, chemical or nuclear change involving one mole of a substance.
What is molar enthalpy?
400
The total molar enthalpy produced by ∆H= +2657.4KJ ∆H= -1574KJ ∆H= -1209KJ
What is ∆H= -125.6KJ
400
600 mL of water is in an electric kettle, it is heated from 20°C to 85°C. The amount of heat that flows into the water is. [c of water is 4.18 J/(g•°C)]
What is 163 KJ
400
When you get a hot coffee what reaction takes place and explain
What is an exothermic reaction because the system is loosing energy in the form of heat?
400
∆H is equal to a few things. Name something that is equal to ∆H
What is ∆H=±q ∆H=∆H/n ∆H= n∆H
500
A change in the protons or neutrons in an atom resulting in the formation of new atoms.
What is a nuclear change?
500
Using the standard heat of formations equation calculate the molar enthalpy of combustion of methane fuel. (CH4 + 2O2 ---> CO2 + 2H2O)
What is -890.7 KJ/mol CH4
500
If 26.51 g of hexane (C6H14) are burned in a bomb calorimeter containing 5.65kg of water, what is the molar heat of combustion of hexane if the water tempature rises 20.0°C to 75.4°C? c of water is 4.18J/g°C
What is 4.25x10^6 J
500
When ∆H= + 34564KJ the reaction is.
What is an endothermic reaction
500
2NO ---> N2 + O2 - 180.6KJ is an example of a a)Exothermic reaction b)Endothermic reaction c)Neither d)Nuclear reaction
What is c because a reaction can not have a negative