Posted in Dimensional Analysis

Metric Prefixes

prefix symbol multiplier to base unitex:equivalence to base unit (meters)
gigaG 1,000,000,000 or 1E9 1 Gm = 1E9 m
or
1 Gm = 1,000,000,000 m
megaM1,000,000 or 1E61 Mm = 1E6 m
or
1 Mm = 1,000,000 m
kilok1,000 or 1E31 km = 1E3 m
or
1 km = 1,000 m
dekada10 or 1E11 dam = 1E1 m
or
1 dam = 10 m
decid0.1 or 1E-11 dm = 1E-1 m
or
1 dm = 0.1 m
centic0.01 or 1E-21 cm = 1E-2 m
or
1 cm = 0.01 m
millim0.001 or 1E-31 mm = 1E-3 m
or
1 mm = 0.001 m
microu0.000001 or 1E-61 um = 1E-6 m
or
1 um = 0.000001 m
nanon0.000000001 or 1E-91 nm = 1E-9 m
or
1 nm = 0.000000001 m
picop0.000000000001 or 1E-12 1 pm = 1E-12 m
or
1 pm = 0.000000000001 m

Posted in Redox Reactions

How to Identify Oxidized and Reduced Elements

Consider the formation of the iron(III) ion and the cerium(III) ion when the iron(II) ion and the cerium(IV) iron react:

the redox reaction showing the formation of an iron (III) ion and a cerium (III) ion from an iron (II) ion and a cerium (IV) ion illustrates the oxidation of iron and the reduction of cerium

The Oxidized Element: Fe

Iron’s charge became more positive. If you can only lose or gain electrons (note: electrons carry a charge of negative one), did iron lose negative charge or gain negative charge from the initial +2 ion to the final +3 ion?

The iron (II) ion lost an electron to produce a more positive iron (III) ion:

+2 – (-1) = +2 + 1 = +3

Note: e- = -1 charge

A loss of negative charge = a loss of electrons and in the half-reaction for iron, electrons will be on the products side to show how it has detached from the initial iron (II) ion and has produced the final iron (III) ion.

Acronym: O.I.L.

Oxidized ions lose electrons (O.I.L.) to become more positive and therefore, the element whose ions are oxidized will be the oxidized element.

Iron is Oxidized

The Reduced Element: Ce

Cerium’s charge became more negative. If you can only lose or gain electrons (note: electrons carry a charge of negative one), did cerium lose negative charge or gain negative charge from the initial +4 ion to the final +3 ion?

The cerium (IV) ion gained an electron to produce a more negative cerium (III) ion:

+4 + (-1) = +4 – 1 = +3

Note: e- = -1 charge

A gain of negative charge = a gain of electrons and in the half-reaction for cerium, electrons will be on the reactants side to show how it has been added to the initial cerium (IV) ion and has produced the final cerium (III) ion.

Acronym: R.I.G.

Reduced ions gain electrons (R.I.G.) to become more negative and therefore, the element whose ions are reduced will be the reduced element.

Cerium is Reduced

Posted in Uncategorized

Types of Solids: Classification of Solids

Crystalline vs Amorphous Solids

Crystalline solids are solids that consist of atoms, molecules, or ions stacked together in a regular pattern [lie in an orderly array] and have a long-range order.

Types and Examples of Crystalline Solids:

  • Molecular solids (sucrose)
  • Network-Covalent solids (boron, quartz crystal silicon dioxide, black phosphorous)
  • Metallic solids (s- and d-block elements)
  • Ionic solids (sodium chloride, potassium nitrate, copper (II) sulfate pentahydrate)

Amorphous solids are solids that consist of atoms, ions, or molecules that have no order/ short-range order and lie in a random jumble.

Types and Examples of Amorphous Solids:

  • Molecular solids (paraffin wax)
  • Glass (quartz glass silicon dioxide- molten silicon dioxide cooled rapidly)

Crystalline Solids