Acids and Bases
When mixing acid and water, do you:
a) Add acid to the water or;
b) Add water to acid
Describe the structure of an atom.
Dense nucleus centre containing neutrons and protons with a large electron cloud surrounding it.
This element has atomic number 7
What is Nitrogen?
This many electrons are in the 3d subshell of an neutrally charged Iron atom
6
A bottle of soft drink is opened, releasing the pressure above the liquid. What happens to the amount of CO₂ dissolved in the liquid?
The dissolved CO₂ decreases and gas escapes as bubbles, Henry's Law
Describe what a buffer does in the context of an acid or base.
Buffers are solutions which maintain pH in an approximate range when acids or bases are added to solution.
They are made up of weak acids and their conjugate base (or vice versa)
These are the three component particles which make up atoms
What are electrons, protons and neutrons?
The most abundant element in the human body by mole
What is Hydrogen?
How many Hydrogens are in this molecule?
12
A gas in a sealed tube is heated up. What happens to the pressure of the system?
The pressure increases
What is Charles' Law?
pH = pKa + log([A-]/[HA])
You want to create a solution with pH=4.5
You have 0.1M Acetic acid (pKa=4.76) and its conjugate base, sodium acetate. What concentration of sodium acetate do you need to buffer at pH=4.5?
0.055M of sodium acetate
(sub in pKa = 4.76 and [HA]=0.1M and solve for [A-])
How many different elements appear naturally on Earth, and what is the heaviest naturally occuring element?
94, Plutonium
The name of the 17th group of the Periodic Table
What are the Halogens?
Describe what a mole is
What is the number of particles required to convert atomic mass units to grams?
A system at equilibrium contains reactancts for a reversible exothermic reaction (forwards reaction is exothermic).
N2 + 3H2 <=> 2NH3
The system is heated up. What happens?
The system performs the reverse reaction at a higher rate.
This is Le Chatelier's Principle