UPCAT Chemistry Stoichiometry

Stoichiometry

• Chemical formulas can be molecular or empirical
• Molecular formula: actual number of atoms in a molecule, e.g. C2H6
• Empirical formula: simplest whole number ratio of atoms, e.g. CH3

Nomenclature

• Ionic compounds:
  • Monoatomic non-metal: -ide
  • Polyatomic:
    • Several O atoms: -ate
    • Less O atoms: -ite
• Transition metals:
  • Smaller charge: -ous
  • Larger charge: -ic
  • Example: Fe2+ is ferrous, Fe3+ is ferric

Quantum Numbers

• Describe an electron and serve as solutions to the Schrödinger wave equation
• n (principal/shell): distance of orbital from nucleus, possible values: 1, 2, 3, 4, 5
• ℓ (azimuthal/angular shape of orbital subrange): possible values: 0, n-1
• ml (magnetic): orientation of orbitals, possible values: -l, +l
• ms (spin): direction of magnetic spin, possible values: ½, -½

Subshells and Shells

• Subshells:
  • s: 1 orbital, 2 electrons
  • p: 3 orbitals, 6 electrons
  • d: 5 orbitals, 10 electrons
  • f: 7 orbitals, 14 electrons
  • g: 9 orbitals, 18 electrons
• Shells:
  • 1st shell: 1s, 2 electrons
  • 2nd shell: 2s, 2p, 8 electrons
  • 3rd shell: 3s, 3p, 3d, 18 electrons
  • 4th shell: 4s, 4p, 4d, 4f, 32 electrons

Taxonomic Ranking

• Mnemonic: Dear King Philip Came Over For Great Spaghetti
• Taxonomic ranks from general to specific:
  • Domain: Eukarya
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Mammalia
  • Order: Carnivora
  • Family: Hominidae
  • Genus: Homo
  • Species: Homo sapiens

Species to Remember

• Found in the Philippines:
  • Pithecophaga jefferyi (Philippine eagle)
  • Bubalus mindorensis (tamaraw)
  • Bubalus bubalis (carabao/water buffalo)
  • Jasminum sambac (sampaguita)
  • Musa textilis (abaca)
  • Musa squamosa (banana)
  • Passer montanus (maya bird)
  • Chanos chanos (bangus)
  • Mangifera indica (mango)
  • Pterocarpus indicus (narra)
  • Macaca fascicularis (Philippine macaque)
  • Oryza sativa (rice)
• Model organisms:
  • Drosophila melanogaster (fruit fly)
  • Escherichia coli
  • Saccharomyces cerevisiae (baker's yeast)
  • Danio rerio (zebrafish)
  • Mus musculus (house mouse)

Genetics

• True-breeding: produces only the same variety as the parent
• Hybridization: crossing of two true-breeding varieties
• P generation: parent
• F1 generation: first filial
• Allele: alternative versions of a gene
• Dominant: determines the organism's appearance
• Recessive: no noticeable effect on the organism's appearance
• Homozygous: gene with a pair of identical alleles
• Heterozygous: gene with two different alleles
• Phenotype: an organism's appearance or observable traits
• Genotype: genetic makeup
• Monohybrids: heterozygous for one particular character
• Dihybrids: heterozygous for two particular characters
• Pleiotropy: having multiple phenotypic effects, especially in alleles
• Epistasis: phenotypic expression of a gene at one locus alters that of a gene at a second locus
• Quantitative characters: vary in the population in gradations along a continuum

This quiz covers stoichiometry concepts including molecular and empirical formulas, ionic and transition metal nomenclature, and chemical formulas. Review for UPCAT exams.