Sec 4E Chemistry Summary Notes Chapter 1 Experimental Chemistry

Flashcards covering experimental design, common physical quantities and their units, laboratory apparatus, methods of gas collection, drying agents, and various purification and analysis techniques including different types of separations and chromatography, as well as methods for determining substance purity.

Burette

An apparatus used to accurately measure out a range of liquid volumes to the nearest 0.05 cm³ (e.g., 24.00 cm³).

Pipette

An apparatus used to accurately measure out fixed volumes of liquids (e.g., 20.0 cm³ or 25.0 cm³).

Measuring cylinder

An apparatus used to measure a range of liquid volumes to the nearest 0.5 cm³.

Gas syringe

An apparatus used to measure the volume of gases.

Displacement of water (gas collection)

A method for collecting gases that are insoluble or slightly soluble in water; gas density does not affect collection.

Downward delivery (gas collection)

A method for collecting gases that are denser than air, regardless of their solubility in water.

Upward delivery (gas collection)

A method for collecting gases that are less dense than air, regardless of their solubility in water.

Concentrated sulfuric acid (drying agent)

A drying agent used for neutral and acidic gases (e.g., O₂, H₂, CO₂, Cl₂, HCl, SO₂), but not for alkaline gases like ammonia due to reaction.

Quicklime (calcium oxide) (drying agent)

A drying agent used for alkaline gases (e.g., ammonia), but not for acidic gases due to reaction.

Fused calcium chloride (drying agent)

A drying agent suitable for all gases except ammonia, as it reacts with calcium chloride.

Magnetic attraction (separation)

A technique to separate a mixture of magnetic solids (e.g., iron, cobalt, nickel) from non-magnetic solids.

Sieving (separation)

A technique to separate solids of different particle sizes using a sieve with suitable pore size.

Sublimation (separation)

A technique to separate a substance that changes directly from solid to gaseous state upon heating, from other stable solids.

Filtration (separation)

A technique to separate an insoluble solid (residue) from a liquid (filtrate).

Evaporation to dryness (separation)

A technique to separate a dissolved solid that does not decompose upon heating from its solvent by vaporizing all the solvent.

Crystallisation (separation)

A technique to separate a dissolved solid that decomposes upon heating, or to obtain a pure solid from a saturated solution, by cooling for crystal formation.

Simple distillation (separation)

A technique to separate a pure solvent (liquid) from its solution based on different boiling points of solute and solvent.

Separating funnel (separation)

An apparatus used to separate immiscible liquids (heterogeneous mixtures) that form distinct layers.

Fractional distillation (separation)

A technique to separate miscible liquids with different boiling points (homogeneous mixtures).

Paper chromatography

A separation technique based on the principle that different components of a mixture have different solubilities in a given solvent, causing them to travel different distances on paper.

Locating agent

A substance applied to a chromatogram of colourless compounds that reacts with them to form visible, coloured spots.

Rf value

The ratio of the distance travelled by a substance to the distance travelled by the solvent on a chromatogram, constant under given conditions.

Pure substance

A substance made up of one single element or compound, characterized by fixed melting and boiling points.

Mixture

Two or more substances that are not chemically combined, which melt and boil over a range of temperatures due to impurities.

Effects of impurities

Cause a substance's melting point to decrease, its boiling point to increase, and melting and boiling to occur over a range of temperatures.