States of Matter & Atomic Structure

States of Matter & Atomic Structure

• Electrons have the smallest mass because they are elementary particles, thus having essentially no mass.
• A positive ion has more protons than electrons (p > e-).
• A negative ion has more electrons than protons (e- > p).
• If element X has a 3+ charge, it has three more protons than electrons.
• If element X has a 3- charge, it has three more electrons than protons.
• Atomic number is equal to the number of protons.
• Evaporation occurs on the surface of a molecule at a specific temperature.
• Boiling occurs at any temperature and involves all molecules.
• Heating a liquid causes particles to gain kinetic energy and intermolecular forces to break.
• Dissolving is a process that occurs before a solid, iodide, or lead is formed.
• Gases travel fastest.
• The formation of a white ring of ammonium chloride takes several minutes because gas particles move in random directions.

Polymers

• Ethene can be converted into poly(ethene).

Atomic Structure Definitions

• An atom has the same number of protons, neutrons, and electrons.
• Atomic number is the number of protons only.
• Mass number is equal to the number of protons plus neutrons.

Complete vs Incomplete Combustion

• Complete combustion produces carbon dioxide and water.
• Incomplete combustion occurs when there is insufficient oxygen/air.
• Carbon monoxide is poisonous because it reduces the amount of blood that transports oxygen.

Compounds

• A compound contains two different elements combined together.

Flame Tests for Ions

• Lithium ions (Li+) produce a red flame.
• Sodium ions (Na+) produce a yellow flame.
• Potassium ions (K+) produce a lilac flame.
• Calcium ions (Ca+) produce an orange-red flame.
• Copper ions (Cu+) produce a blue-green flame.
• Sulfur dioxide is indicated by a blue color.

Chromatography

• The baseline must be drawn in pencil as it is not soluble and won’t dissolve.

Fuels

• A fuel releases heat energy when burned.

Gas Volume Measurements

• A measuring cylinder is a suitable apparatus for measuring gas volumes.
• A gas syringe should be quickly connected so as little gas is lost as possible.

Chlorine Ion Test

• Add nitric acid (to test it).
• Add silver nitrate (to react it).
• A white precipitate forms.

Magnesium Oxide

• Magnesium oxide burns with a bright white flame.
• White powder forms.

Catalysis

• Copper powder, when heated, increases the rate of reaction as it gives particles enough energy to react.

Chemical Reactions

• The formula of the compound formed when iron reacts with oxygen (O2) is Fe2O3.
• Reactions that produce carbon dioxide include the complete combustion of alkanes and the thermal decomposition of copper (II) carbonate.
• Argon is a trace gas with the highest percentage in unpolluted air.
• Nitrogen dioxide dissolves in water to form nitric acid.
• Sulfur dioxide is another pollutant gas formed in acid rain.

Reactions

• The reaction stops when there is no more fizzing or bubbling.

Crude Oil

• Crude oil is separated into fractions by fractional distillation
• Crude oil is first heated/vaporized.
• Vapor enters at the bottom of the fractionating column.
• The column is cooler at the top and warmer at the bottom.
• Fractions are then separated according to boiling point.

Importance of Cracking

• Cracking is important in the oil industry because it breaks long polymers to produce shorter chains of alkenes.

Isomers vs Isotopes

• Isomers have the same molecular formula, but different structural formulae.
• Isotopes are variations of an element with different numbers of neutrons.

Formulae

• Ar = p + n

Catalysts

• Silica is a catalyst for cracking.

Reaction Conditions

• Ultraviolet (UV) radiation is needed for ethane to react with bromine.

Saturated Compounds

• A saturated compound has only single bonds.
• No other atoms can be added to it.

Oxygen Test

• Oxygen relights or ignites a glowing splint.

Identifying Solutions

• Chemical tests can identify a solution in an unlabeled bottle.
• Add sodium hydroxide solution and identify ions. A green precipitate indicates iron (II) / Fe2+. A brown precipitate indicates iron (III) / Fe3+.
• Next add silver nitrate (to a new or fresh solution) to identify halogens. A white precipitate indicates chloride / Cl-. A cream precipitate indicates bromide / Br-. A yellow precipitate indicates iodide / I-.

Hydrogen Test

• Hydrogen produces a "squeaky pop" with a lighted splint.

Ionic Bonding

• Ionic bonding is electrostatic attraction between oppositely charged ions.

Isotopes

• Isotopes are atoms with the same number of protons.

Non-Metals

• Non-metals do not conduct electricity.

Chemical Equation

• The chemical equation for copper carbonate decomposition is CuCO3 -> CuO + CO2.

Aluminum Uses

• Aluminum is suitable for making cans because it is non-toxic and does not react with drinks.

Concordant Results

• Concordant results are results that are 0.2cm3 of each other.

Reactants

• Mixing silver nitrate and sodium chloride produces silver chloride.

Neutron Properties

• A neutron has a relative mass of 1 and a charge of 0.

Isotopes

• Isotopes have the same number of protons but different numbers of neutrons.

Distillation

• Distillation is used to obtain pure water.

Condensers

• Water is cooled, then condensed in the condenser.

Chromatography Paper

• Pour water into a beaker.
• Place paper in the water so that the food colorings are above the level of the solvent.
• Leave the paper until the solvent reaches near the top of the paper.
• Take out the paper and leave it to dry.

Rf Value

• The Rf value is calculated as the distance moved by the solvent/dye divided by the distance moved by the solvent front.

Incomplete Combustion Products

• Incomplete combustion produces carbon monoxide, carbon, and water (vapour).

Isomers

• Isomers have the same molecular formula but different structural formulae.

Disposing of Polymers

• Polymers remain in landfills for thousands of years and they are inert.
• Burning polymers produces greenhouse gases.

Chemical Test for Halides

• Add nitric acid, then add silver nitrate.
  • Cream precipitate indicates Bromide (Br-).
  • White precipitate indicates Chloride (Cl-).
  • Yellow precipitate indicates Iodide (I-).

Physical Tests for Water

• Measure its boiling point = 100°C.
• Measure its freezing point = 0°C.
• If boiling point is more than 100°C or the freezing point is lower than 0°C, it is impure.

Chromatography Steps

• Draw a start line in pencil.
• Use the same type of food colorings and chromatography paper.
• Place spots of the food dyes on the start line.
• Place the paper in the beaker, with the start line above the solvent.
• Remove the paper when the food dye stops moving.
• Remove the paper from the beaker to allow it to dry.

Sodium Hydroxide Properties

• Sodium hydroxide can flow when molten but not solid because in molten state, ions are free to move and can flow easily.

Bio-Polyester

• A bio-polyester is a polyester that is biodegradable.

Atomic Number

• Atomic number = number of protons.

Separation Techniques

• Solid --> aqueous solution requires a separating substance/method such as crystallization.

Importance of Cracking in the Oil Industry

• Cracking breaks long polymers into shorter chains of alkenes.
• Shorter chains are more flammable and, so are more useful for fuels.
• Cracking produces alkenes.
• Alkenes are more useful for making plastics & polymers.

Catalyst Properties

• Catalysts provide an alternative pathway with a lower activation energy.

Test for Carbonate Ions (CO3-2)

• Contains the compound CO3-2.
  • Add dilute acid to the compound.
  • Bubble the gas released through limewater.
  • Lime water turns cloudy if a carbonate ion is present.
  • If a carbonate compound is present, the effervescence should be seen as CO2 gas.
  • That CO2 will form a white precipitate of calcium carbonate when bubbled through limewater.

Covalent Bonds

• Covalent bonds involve a shared pair of electrons.
• These shared electrons are attracted to the nuclei.

Expected Gas Volume Calculation

• Since the gas reacts with O2 = 21%, the volume given X remaining amount of air /100.
• Then 21-100 = 79%.

Factors to Keep Constant in an Experiment

• A student uses a method to investigate the reaction between sodium hydroxide solution and dilute hydrochloric acid.
• State two factors that the student must keep constant to make this a valid investigation:
  1. The concentration of Sodium hydroxide.
  2. Temperature of Sodium hydroxide.

Testing for Carbonate Ions

• A description that refers to the following three points:
  • M1 add (dilute) hydrochloric acid (to sodium carbonate).
  • M2 bubble/pass the gas through limewater OR test M2 depends on M1: add acid, not limewater.
  • M3 (limewater) turns milky/cloudy. M3 depends on limewater.

Metals

• Metals conduct electricity