M5 - Equilibrium and Acid Reactions
Define Le Chatelier's pinciple
Le Chatelier's principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish an equilibrium.
Definition of Arrhenius acid
A neutral substance that forms protons (H+) in an aqueous solution
Alkene + Hydrogen (with Ni catalyst)
What is the product? It it a substitution or addition reaction?
2. Addition reaction
What colour does Ca2+ cation produce in a flame test
brick red flame colour
Solubility Equilibrium expression
Ksp = [products]/[reactants]
What will cause this equilibrium reaction to the right?
2HI(g) <=> H2(g) + I2(g)
Delta H = -52kJ
Adding more of the reactant or decreasing the temperature
Bronsted-Lowry definition of acids and bases
Acids donate protons and bases accept protons
Name the catalyst required for the hydration of an alkene
Acid catalyst
Describe 2 tests that you could use to determine if an unknown solution contains CO3 2-
1. Add an acid
2. use red litmus paper and it will turn blue
0.0560 - How many significant figures?
3
Main 3 features of collision theory
1. reactant particles collide at an effective orientation
2. Frequency of collisions between reactant particles
3. Whether the energy between particles in a collision is equal to, or greater than the activation energy
Provide an example of an amphiprotic molecule
water or hydrogen carbonate (HCO3-)
Which would have a higher BP - primary alcohol or branched alcohol with the same formula? Why?
Primary alcohol - branching weakens the intermolecular forces between individual molecules hence higher BP
Are acetate ion or hydroxide ions more likely to form a precipitate?
Hydroxide
How do you ensure reliability in a titration?
Repeat experiment multiple times and remove any outliers - (greater 0.2ml variation)
Is Le Chatelier's principle valid for combustion reactions? Explain why?
No, combustion reactions are irreversible
Conjugate acid for NH3
NH4+
What product is formed when you react a secondary alcohol with an oxidant?
Ketone
Outline a test to identify alkenes
Bromine water test - where bromine water turns orange/brown to clear
If the temperature increases as the chemical reaction proceeds, is it endothermic or exothermic?
Exothermic
Why do equilibrium systems require a closed system?
Closed systems are required so that no reactants or products escape, thus reducing the chance of successful forward and reverse reactions
A 0.1M solution of acetic acid is known to only ionise about 1.3%. Calculate the pH of the solution.
2.9
Write a word equation for saponification.
Triglyceride + sodium hydroxide -> glycerol + fatty acid salt (soap)
What standard is used in NMR?
Tetramethylsilane (TMS) - produce a strong single peak and the hydrogen atoms are maximally shielded from the magnetic field.
What 3 things due manufacturers need to consider when designing a chemical synthesis process?
Accessibility of reagents
location of plant
Safety hazards
transportation
Environmental impacts