Chem U7- Molar Mass, % comp

Molar Mass

The number of GRAMS of a substance which is EQUAL to 1 Mole of a substance.

Mass of 1 mol

-PT for Elements

-MUST calculate for compounds

Multiplier

Any number outside of parenthesis which MULTIPLIES out to ALL inner elements, increasing that elements total number of moles

EX: (NH4)2

2 X N = N2; H4 × 2 = H8

Hydrates

Solids that contain a FIXED NUMER of H2O molecules as A PART of their structure

EX:Na2(CO3) * 10H2O

Molar Conversion

GMA

First find molar mass of compound(s), then use that number as CONVERSION FACTOR

Formula Unit

AKA Avogadro’s Number (6.022×10²³ )

Terms: “MOLECULE”, “ATOM” are __________ ____.

Percent comp

Gives the PERCENTAGE (%) of each element in a compound by MASS.

Calculated by DIVIDING the TOTAL MASS of EACH Element by a molar mass of the compound.

**PERCENT BY MASS

Empirical formula

Formula which gives the PROPORTIONS of present elements in a compound but NOT the actual Numbers or Arrangement of atoms

RATIO IS 1:2:1 ie H2O

Molecular Formula

Chemical formula based on chemical analysis and Molecular Weifht

MULTIPLE OF EMP FORMULA

Require BOTH MOLAR MASS and EMP FORMULA to FIND

Lowest reduction

Emp formulas is the ___________ ____________ of elements present

EX: O3C3N3Cl3, H2O, XY3

Can be reduced

Molecular Formula ____ _____________ to lower numbers per element

Molecular Formula EX: C9H18N6 C6H12O6