moles and molar calculations

what is Avogadro’s constant ?

1 mole = 6.022 × 10(23) atoms

molar mass =

atomic masses x subscript no.

what is the molar mass of 1mol of glucose ?

180g

moles =

mass/molar mass

the molarity of a substance refers to…

the no. of moles of a compound dissolved in 1L of liquid

molarity is measured in

Molar (M)

a 1M solution has

1mol of compound dissolved in 1L of solvent

what does Beer’s Law state ?

higher the conc. higher the absorbance (AU)

absorbance

quantity of light absorbed by solution

transmittance

quantity of light that passes through a solution

our eyes see light

that is NOT absorbed

Lamberts Law

greater the thickness greater the absorption

in a cuvette the path of light is standardised

to 1cm

what equation represents the Beer-Lambert law

A = Ecl

the pH scale measures

the acidity of a substance

acid

any sub that releases protons - donor

base

proton acceptor

strong acids

completely dissociate

weak acids

incompletely dissociate

equation for pH

equation for pKa

Ka

acid dissociation constant

pKa

pH at which half of acid is dissociated

Henderson-Hasselbalch equation

in water sodium hydroxide…

completely dissociates

pOH =

-log (OH-)

pH + pOH =

14

what is a lower pKa indicative of ?

stronger acid