3:14

3:14 (Triple only) draw and explain reaction profile diagrams showing ΔH and activation energy

Below is a diagram showing the reaction profile for the reaction of hydrogen with oxygen, which is EXOTHERMIC:

The activation energy is the minimum amount of energy required to start the reaction.

For an exothermic reaction, the products have less energy than the reactants. The difference between these energy levels is ΔH.

For an exothermic reaction, more energy is released when bonds are formed than taken in when bonds are broken.

 

Below is a diagram showing the reaction profile for the thermal decomposition of calcium carbonate, which is ENDOTHERMIC:

The activation energy is the minimum amount of energy required to start the reaction.

For an endothermic reaction, the products have more energy than the reactants. The difference between these energy levels is ΔH.

For an endothermic reaction, more energy is taken in to break bonds than is released when new bonds are formed.

Past paper questions

2019-05-13T15:24:09+00:00Categories: PastPaperQuestions|Tags: , , , |
Select a set of flashcards to study:

     Terminology

     Skills and equipment

     Remove Flashcards

Section 1: Principles of chemistry

      a) States of matter

      b) Atoms

      c) Atomic structure

     d) Relative formula masses and molar volumes of gases

     e) Chemical formulae and chemical equations

     f) Ionic compounds

     g) Covalent substances

     h) Metallic crystals

     i) Electrolysis

 Section 2: Chemistry of the elements

     a) The Periodic Table

     b) Group 1 elements: lithium, sodium and potassium

     c) Group 7 elements: chlorine, bromine and iodine

     d) Oxygen and oxides

     e) Hydrogen and water

     f) Reactivity series

     g) Tests for ions and gases

Section 3: Organic chemistry

     a) Introduction

     b) Alkanes

     c) Alkenes

     d) Ethanol

Section 4: Physical chemistry

     a) Acids, alkalis and salts

     b) Energetics

     c) Rates of reaction

     d) Equilibria

Section 5: Chemistry in industry

     a) Extraction and uses of metals

     b) Crude oil

     c) Synthetic polymers

     d) The industrial manufacture of chemicals

Go to Top