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physical chemistry - Coggle Diagram
physical chemistry
energetics
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specific heat capacity
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Since an increase in the temperature of the water means a decrease in the energy of the chemicals, to find the enthalpy change of the reaction, use ΔH = - m c ΔT
Enthalpy change is commonly given per mole, and the molar enthalpy change is given in
kilojoules per mole.
molar enthalpy change
Q/ J divide by 1,000 to get Q/ kJ
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energy level diagrams
energy level diagrams can be used to show the energy of the reactants compared to the products of a reaction
exothermic reaction: energy is released to surroundings, so reactants have more energy than products
endothermic reactions: energy is taken in from surroundings, so reactants have less energy than products
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rates of reactions
experiments
surface area
Add dilute hydrochloric acid to the conical flask. Use a delivery tube to connect this flask to an inverted measuring cylinder upside down in a water trough. Add calcium carbonate chips into the conical flask and close the bung and measure the volume of gas produced in a fixed time using the measuring cylinder. Repeat with different sizes of calcium carbonate chips
concentration
Add sodium thiosulfate solution to a flask with dilute hydrochloric acid into a measuring cylinder. Draw a cross on a piece of paper and put it underneath the flask, then add the acid into the flask and immediately start the stopwatch. Look down at the cross from above and stop the stopwatch when it can no longer be seen and repeat using different concentrations of sodium thiosulfate solution.
temperature
Dilute hydrochloric acid is heated to a set temperature using a water bath. Add the dilute hydrochloric acid into a conical flask. Add a strip of magnesium and start the stopwatch. Stop the time when the magnesium fully dissolves. Repeat at different temperatures and compare results
use of a catalyst
Add hydrogen peroxide into a conical flask. Use a delivery tube to connect this flask to a measuring cylinder upside down in water trough. Add the catalyst manganese(IV) oxide to the conical flask and close the bung. Measure the volume of gas produced in a fixed time using the measuring cylinder. Repeat experiment without the catalyst of manganese(IV) oxide and compare result
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catalysts
a substance that increases the rate of a reaction, but is chemically unchanged at the end of the reaction
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