Chemistry Flashcards
Physical Property
characteristics of a substance that can be determined without changing its makeup
- density, lustre, clarity, viscosity, ductility, colour, texture, etc
Chemical Property
characteristics determined when the composition of the substance is changed (how it behaves/ reacts)
- reactivity with water, acids, or bases
Particle theory
1) all matter is composed of particles.
2) particles are always in motion
3) particles held together by strong attractions (forces)
4) spaces between particles (that are large compared to particles themselves)
5) each substance has a unique particle
6) temperature affects the speed of particles
Combining capacity
maximum bonds an atom can make
Subatomic particles
neutrons (n), protons (+), electrons (-)
Periodic Table
- atomic number = # protons
- mass number = protons + neutrons
Define the two different types of ions.
Anion - negatively charged
Cation - positively charged
What elements are involved in ionic bonding?
Metals & non-metals
Physical change
- does not produce new substance
- usually reversible
Chemical change
- produces 1+ new substances
- always irreversible
What are some examples of evidence that a chemical change took place?
- change of colour
- precipitate forms in a liquid
- heat or light is absorbed/ produced
- bubbles of gas formed
Ionic compound
1+ positively charged metal ion and 1+ negatively charged non-mental ion
Explain what happens in an ionic bond.
- atoms trying to attain a full valence shell (octet rule)
- transfer of electron(s) from a metal to a non-metal
- metal becomes ‘isoelectronic’ (or likened) to a noble gas
- the opposite charges of the two atoms binds them together
What elements are involved in a covalent compound?
2+ non-metals
Diatomic Gases
elements that exist as two atoms together (HOFBrINCl)
Explain what happens in a covalent bond.
Both non-metals want to gain electrons, but instead of transferring them they share their valence electrons
Reactants
substances that react together in order to form new products
Products
new substances made by the chemical RXN
List the three equations in which reactions are symbolized in
1) Word
2) Chemical
3) Balanced chemical
5 Basic Reactions (use examples)
Synthesis: A + B → AB Decomposition: AB → A + B Single Displacement: X + AB → A + XB Double Displacement: XY + AB → AY + XB Combustion: Hydrocarbon fuel + oxygen → carbon dioxide + water vapour + energy
What is the critical difference between complete and incomplete combustion? Why is it critical?
In complete combustion carbon dioxide, water and energy are the only products. During incomplete combustion, carbon dioxide and carbon are produced as well. Carbon monoxide is deathly because it prevents oxygen flow in the body. Carbon Dioxide is an odourless, colourless gas that latches onto red blood cells.
What is the ideal reactant (fuel vs oxygen) ratio to ensure complete combustion?
Fuel needs to rest with an excess of oxygen to ensure complete combustion.
Activity Series for Metals
list of metals in order of reactivity/ their likelihood of displacing other metals in reactions (single displacement)
- higher metals can displace lower ones only
What are the 4 factors that affect the rate of reaction?
1) Temperature
2) Concentration
3) Surface Area
4) Catalyst
What must happen for a reaction to occur?
Particles must come into contact with a certain amount of force and the correct orientation (+/-)
Catalyst
- increases rate of RXN but is NOT used up/ altered during it (can be later removed)
- does not become a reactant!
- changes reactants’ orientation to collide more effectively
- ex: fridge delays the rotting process (bio/chem rxns) of mold and bacteria
Describe acids
- release H+ ion
- sour
- dissolves well in water
- conducts electricity well
- usually starts with H
- no usual feeling
- ex: vinegar, vitamin C, carbonic acid (aka soda)
Describe bases
- release OH- ion
- bitter
- dissolves well in water
- conducts electricity well
- usually has (OH) in it
- slippery
- ex: baking soda, food preservatives, drain cleaner, soap
pH Scale
- measures concentration of acids/ bases
- 0 to 14 (acidic = low, basic = high)
- 7 = neutral (water)
- logarithmic; each step is 10x +/- concentrated
Neutralization
- adding water = bring pH closer to 7 = diluting
- ACID + BASE → WATER + SALT
VSEPR
= Valence Shell Electron Pair Repulsion theory
- electron pair geometry = considers shape of all pairs
- molecular geometry = considers shape of molecule (bonded pairs)
Polar Covalent bonds
One atom holdes electrons more strongly than the other (i.e. higher EN)
- 0,5 - 1.7 EN
List the different types of VSPER structures
- linear
- triangular planar
- bent
- tetrahedral
- trigonal pyramidal
- angular bent
- triangular bipyramidal
- octahedral
Describe how you would draw a diagram of molecules showing bond dipoles.
- element letters
- arrows (+) ⟼ (-)
- δ+ and δ- symbols