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32 Cards in this Set
- Front
- Back
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What is the formula for the enthalpy of combustion |
Eh=cm/\T |
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What is the enthalpy of combustion |
The energy released when one mole of a substance burns completely in excess oxygen |
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What does each of the letters in the enthalpy of combustion formula stand for |
Eh= enthalpy (kJ mol ^-1) c = specific heat capacity of water (4.18 kJ kg-1 °C^-1) m = mass of water being heated (kg) /\T= change in temp (°C) |
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What is collision theory |
For a chemical reaction to occur: -reacting particles must collide -particles must collide with sufficient kinetic energy (activation energy) -particles must collide with correct alignment |
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How does an increase in temperature affect the number of successful collisions |
Increase temp = more kinetic energy Means more have kinetic energy >Ea => more particles have the potential to collide successfully |
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How does an increase in concentration affect the number of successful collisions |
Greater concentration = more particles in given volume More particles = more collisions = more successfull collision |
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How does a decrease in particle size affect collision theory |
Decrease particle size = larger SA = more space for collisions = more successfull collisions |
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What is the percentage yield equation |
% yield= actual yeild x100 Theoretical yield |
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What is the theoretical yield |
How much product would be made from a specified mass/volume of reactants if the reaction was perfect |
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How do you calculate theoretical yield |
Use a balanced equation |
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What is the actual yield |
The mass/volume that is actually made |
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How do you calculate average rate |
Avg. Rate = change in outcome change in time |
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What is a potential energy diagram |
Diagram used to show the energy pathway for a chemical reaction Shows how the potential energy changes as the reaction progresses |
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What does exothermic mean |
Energy is released |
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What does endothermic mean |
Energy is gained |
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Does the diagram show an exothermic or endothermic reaction |
Exothermic |
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Does the diagram show an exothermic or endothermic reaction |
Endothermic |
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What does Ea stand for |
Activation energy |
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What does /\H stand for |
Enthalpy change |
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How does use of a catalyst affect a potential energy diagram |
A catalyst lowers the activation energy of the reaction |
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How is a reversible reaction shown in an equation |
Double headed arrow |
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Is the /\H a +ve or - ve value for an exothermic reaction |
Negative |
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Is the /\H a +ve or - ve value for an endothermic reaction |
Positive |
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What does a kinetic energy distribution diagram show |
Shows how many particles are moving with each value of Kinetic energy |
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How does an increase in temperature affect the kinetic energy of particles |
Gives more particles kinetic energy greater than the Ea =>more particles could collide successfully |
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Which of the first 20 elements are monatomic elements |
Halogens (Helium, Neon, Argon) |
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Which of the first 20 elements are covalent molecular elements |
Hydrogen, Carbon, group 5,6,7 (H, C, Nitrogen, oxygen, Fluorine, Phosphorus, sulfur, Chlorine) |
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Which of the first 20 elements are covalent network |
Boron, Carbon, silicon |
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Which of the first 20 elements are metallic lattise |
Group 1 + 2 & Al (minus hydrogen) (Lithium, Berylium, Sodium, Magnesium, Potassium, Calcium, Aluminium) |
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What is special about Carbon |
It exists as Covalent molecule and covalent network |
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What are Van der Walls forces |
Forces of attraction that exist between atoms or molecules |
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Which are stronger, intermolecular or intramolecular bonds |
Intramolecular bonds |
