Semester 2 Exam Flashcards
Flame Test
Heating an element causes electrons to jump from ground state to excited state.
When returning to ground state, they emit specific wavelengths of light.
Frequency of these wavelengths determine the colour.
What is a fossil fuel
Non renewable resources that are used faster than they can be replaced.
Types of fossil fuels
Coal
Oil
Natural gas
What are biofuels
Fuels derived from plant materials such as grains, sugar cane, vegetable waste and vegetable oils.
Endothermic reaction in terms of bonding
Absorbs energy from its surroundings. More energy is absorbed during bond breaking than is released during bond forming, resulting in a net intake of energy.
Exothermic
Process that releases energy to its surroundings. More energy is released during bond forming than is absorbed during bond breaking, resulting in a net release of energy.
Metallic bonding
Electrons are delocalized in a “sea of electrons” that move freely around positively charged metal ions, allowing metals to conduct electricity and heat.
This bonding is non-directional.
Therefore when a force is applied, the substance can change shape without disrupting the bonding.
Ionic bonding
Positively and negatively charged ions are held together by strong electrostatic forces in a rigid lattice.
The bonding is directional, so when a force is applied, like charges are forced to align and repel each other, causing the substance to break. Hence being brittle.
Monoprotic acid
One ionisable hydrogen per molecule. (HCl)
Weak acid
Partially ionises in a solution.
Catalyst
Provides an alternate reaction pathway with a lower activation energy. This allows a greater proportion of particles to react.
Nanoparticle
Particles in the size range 1-100 nm
Saturated solution
Maximum amount of solute dissolved in a solvent (at a particular temperature).
Unsaturated
Less than maximum amount of solution dissolved in a solvent (at a particular temperature.)
