Chapter 03B: Molecules, Compounds, and Chemical Equations Flashcards Preview

CHE133 - Gen Chem I > Chapter 03B: Molecules, Compounds, and Chemical Equations > Flashcards

Flashcards in Chapter 03B: Molecules, Compounds, and Chemical Equations Deck (15):
1

Molecular mass

Sum of atomic masses (in amu) in a molecule.

2

Formula mass

Sum of the atomic masses (in amu) in a formula unit of an ionic compound

Remember:
formula unit : molecular formula
as
ionic compound : molecular compound

3

Mass percent composition

Mass percent of each element in a compound

mass % = (n) (molar mass of element)   x 100
    (molar mass of compound)

Where n = mol of element in compound

E.g. CO2, n = 2 when calculating mass % of O

4

Calculating empirical formulas

1) % percent --> g --> mol (for each element)

2) Set up unsimplified ratio (framework of empirical formula)
Simplify: divide by the smallest # of mol

3) Change simplified mole ratios to integer subscripts
*If element(s) in ratio are not close to a whole number, multiply the ratio, then round --> empirical formula

5

Combustion analysis

Technique for analyzing compounds, mostly for organic compounds

Uses product mass, reactant composition to determine empirical formula (and eventually molecular formula)

6

Calculating molecular formula from empirical formula

Molecular formula is a multiple of empirical formula

 

Molecular formula = (empirical formula)n

Where n = positive integer

n =              molar mass
                       empirical formula molar mass

7

Chemical reaction

Chemical change; 1+ substances are changed into 1+ new substances

8

Chemical equation

Shorthand notion for chemical reactions

Used for:

- displaying reactants & products
- indicating specific amounts of materials used/produced

9

Organic compounds

Mainly made of C and H
Sometimes with O, N, P, S (+ trace amounts of other elements)

10

C in organic compounds (3 details)

1) C bonds almost always covalently
2) Each [starter] C forms 4 bonds somehow:
        *4 single, 2 double, 1 triple + 1 single, etc.
        *e.g. C2H2 and CH3COOH
3) C can form limitless changes of C atoms (unique)
        *straight, branched, and ring-form

11

Organic compounds --> two subcategories (nomenclature)

Organic compounds                     

Hydrocarbons                              Functionalized hydrocarbons

A image thumb
12

Hydrocarbons

Organic compounds with ONLY C and H

E.g. common fuels

13

Alkanes

Hydrocarbons with only single bonds

14

Alkenes

Hydrocarbons with double bonds

15

Alkynes

Hydrocarbons with triple bonds