Chemistry

1: Basic Concepts

percentage by mass of an element in a compounds = $\frac{mass of element in the compounds}{total mass of compounds} \times 100$
$1 amu = 1.66 \times 10^{- 27} k g$
$N_{A} = 6.022 \times 10^{23}$

\frac{Total particles}{Avogadro’s Number N_{A}} = Moles = \frac{Mass in grams (g)}{Molar Mass (a m u)}

3.01 \times 10^{23}

molecules of

H_{2} O

will

c e

weigh:

a)18gb)9gc)4.5gd)none

6g of

H_{2}

gas is:

a)1 moleb)2 molesc)3 molesd)4 moles

1 mole of $CO_{2}$ has 1 mole of C and 2 moles of O, and hence has 12 grams of C and 32 grams of O
In Combustion analysis
- $Mg (OH)_{2}$ absorbs water
- 50% $KOH$ absorbs $CO_{2}$
mass spectrometer gives $\frac{e}{m}$ ratio of ion or atomic masses
moles AKA gram atoms/molecules/formula units
Arsenic, Fluorine, Iodine and Gold are mono-isotopic
at STP pressure of every gas is

1 amu = 760 torr = 101325 Pa =

Volume = Moles \times 22.414 d m^{3}

volume occupied by 0.2 moles of methane gas at STP

a4.40L)b)4.48Lc)8.96d)2.24L

Sabatier Sender's Reaction: hydrogenation of unsaturated alphatic compounds to get alkanes
Clemmenson: $Ketones \overset{Zn - Hg, HCl}{\to} Alkanes$
Wolf-Kishner: Aldehyde $\overset{Na, liq \cdot NH_{3}}{\to}$
Soda Lime: NaOH + CaO=

Alcohol > Phenols > Ethers

Mixtures of alcohol
- Wood Spirit: 99.99% Methanol
- Absolute Alcohol: 99.99% Ethanol
- Rectified Spirit: 95% Ethanol, 5% Impurities
- Methylated Spirit: 95% Ethanol, 5% Methanol
- Denatured Alcohol: 90% Ethanol, 10% Methanol
Reactivity of Alcohol, When O-H bond breaks, when electrophile attacks, when showing acid nature

Tertiary > Secondary > P r i m a r y

When C-O bond breaks, when nucleophile attacks, when showing basic nature

Tertiary < Secondary < P r i m a r y

Iodoform test: gives ~={yellow}yellow=~ precipitate for compounds with $β - Ch_{3}$ e.g. ethanol
Lucas test:
Alkoxides: salt from an alcohol $C_{2} H_{5} OH + 2 Na ⟶ \underset{alkoxide}{\underset{⏟}{C_{2} H_{5} ONa}}$

TESTS	between	gives	for	example
Iodoform	alcohols	~={yellow}yellow=~ precipitate	compounds with $β - Ch_{3}$	~={green}ethanol=~ and ~={red}methanol=~
Lucas	degree's of alcohol	time difference	Primary: on Heatinng Second: 5-10 mins Tertiary Immediately