OCR Gateway Science - Chemistry C5

Mole

1 _____ of a substance is 6.022�10�� atoms of that substance.

g/mol

The unit used to measure molar mass.

Molar Mass

The mass of an entire molecule.

Relative Atomic Mass

The mass of an individual atom.

Moles

_____ = Mass � Molar Mass

Conserved

Mass is _____ during a reaction.

Reactants

The substance(s) on the left of the arrow.

Products

The substance(s) on the right of the arrow.

Thermal Decomposition

The breaking down of a substance under heat.

Empirical Formula

The simplest way of writing a ratio of each type of atom in a molecule.

Moles

The amount of _____ of each element is divided by the amount of _____ of the element least moles present in one molecule is .

2

The number of hydrogen atoms in the empirical formula for glucose.

Percentage Mass

_____ _____ of Element = Total mass of Element in Compound � Formula Mass of Compound) x 100

Molar Mass

_____ _____ = Mass � Moles

Concentration

The amount of solute in 1dm� of solution.

g

Concentration is measured in __/dm�

Dilute

If more solvent is added, the solution will become more _____.

Concentrated

If more solute is added, the solution will become more _____.

1000

To convert from cm� to dm�, multiply by _____.

Moles

_____ = Concentration x Volume

Volume

_____ = Moles � Concentration

GDA

_____ is the recommended amount of a nutrient which should be ingested each day.

Guideline Daily Allowance

GDA stands for _____ _____ _____.

Sodium Chloride

The scientific name for salt.

Sodium Ions

_____ _____ are mainly sourced from salt and are used in nerve impulse transfer & water balance.

Titration

The method of finding the concentration of a reactant by slowly adding a substance.

Acids

_____ have low pHs.

Alkalis

_____ have high pHs.

Alkali

A soluble base is an _____.

High

Bases have _____ pHs.

Universal Indicator

The substance which changes colour in a substance, dependent on the pH.

Litmus

_____ paper will change to blue in an alkali and red in an acid.

Phenolphthalein

_____ will be pink in an alkali and colourless in an acid.

Salt

Acid + Alkali -> _____ + Water

Hydrogen

Acid + Metal -> Salt + _____

Metal Oxide

Acid + _____ _____ -> Salt + Water

Carbon Dioxide

Acid + Metal Carbonate -> Salt + Water + _____ _____

Neutralisation

The process of adding enough alkali to acid (or vice versa) to result in a neutral substance.

Pipette

A small tube with a bulb at the top which can be pressed to form a vacuum, allowing liquids to be sucked into it.

Burette

A tall cylinder with measurements along it and a tap at the end to slowly let a liquid out.

Acid Concentration

Number of Moles of Alkali = _____ _____ x Volume in dm�

Alkali Concentration

Number of Moles of Acid � Number of Moles of Alkali = _____ _____

24

Number of Moles = Volume of Gas in dm� � __

Limiting Reactant

The substance which is used up first.

Explosion

The rapid expansion of gas.

Gas Syringe

Gas volume can be measured using a _____ _____.

Steeper

The _____ the gradient, the faster the reaction.

Reversible Reaction

A reaction in which both the forward and backward reaction occur at the same time.

Equilibrium

The state at which the rate of reaction for both the forward and backward reactions is equal.

Left

If the concentration of the reactants increase, the equilibrium will be on the _____.

Right

If the forward reaction is exothermic and the temperature is increased, the equilibrium will be on the _____.

Exothermic

A reaction which gives out more energy than it takes in is _____.

Endothermic

A reaction which takes in more energy than it gives out is _____.

Catalyst

A _____ does not change the equilibrium, instead increasing the rate of reaction for both the forward and backward reactions.

Contact Process

The series of reactions used to produce sulfuric acid.

1

Stage __ of the Contact Process is "S + O? -> SO?

2

Stage __ of the Contact Process is "2SO? + O? ? 2SO?

3

Stage __ of the Contact Process is "SO? + H? -> H?SO?

450

Stage 2 of the Contact Process is carried out at approximately __�C

Sulfuric Acid

The name for H?SO?

Vinegar

_____ is a good example of a commonly used weak acid.

Battery Acid

_____ _____ is a good example of a commonly used strong acid.

Lower

Strong acids have a _____ pH than weak acids.

Strong

_____ Acid -> Hydrogen Ions + Other Ions

Weak

_____ Acid ? Hydrogen Ions + Other Ions

Water

When an acid or an alkali is added to _____, it ionises.

H

Acids contain __+ ions.

OH

Alkalis contain __- ions.

Stronger

_____ acids contain more H+ ions.

Precipitate

A solid substance formed when one liquid is poured into another liquid.

Ionic Lattices

Compounds containing metal and non-metal ions form _____ _____.

Spectator Ions

_____ _____ are left out from an equation as they do not change through the reaction.

Silver Nitrate

The substance used to test for halide ions.

Barium Chloride

The substance used to test for sulphate ions.

Evaporating

Solid salts can be separated from a solvent by _____ the solvent.