CH1 - Chemistry Equations

= -m x c x change in temperature/moles

-m is the mass of substance absorbed (usually water)

c is the specific heat capacity (usually 4.12kJ)

= change in concentration of product or reactants / time

1. moles = mass / Ar

2. divide by the smallest

3. apply to the atom

e.g.

Al - 6.75/27 = 0.25

Cl - 26.63/35.5 = 0.75

0.25/0.25 = 1

0.75/0.25 = 3

AlCl3

1. calculate moles of what know

2. use equation to work out what know-finding ratio

3. calculate what trying to find

Mr / empirical mass = [ANS]

[ANS] x empirical formulae

e.g.

AlCl3

Mr - 267

Empirical mass - 133.5

267/133.5 = 2

AlCl3 x 2 = 2AlCl3

= volume of gas / 24dm3

e.g.

6g of Nitrogen

6/24 = 0.25

(P x V / T) = (P2 x V2 / T2)

temperature must be in K = 'c + 273

e.g.

(100x400/473) = (P2x50/473)

P2 = (100x400/50)

P2 = 80kPa

= actual yeild / theoretical yield

e.g.

theoretical yield is just Mr of each atom

= mass of useful / total mass of reactants x100

1. calculate the Mr of each atom

2. calculate the total mass for reactants (include the front numbers)

3. calculate the total mass of wanted products (including the front numbers)

4. apply to formulae

= abundance of each isotope x peak / 100 or total abundance

delta H = delta H1 + delta H2

= energy of bonds broken - energy of bonds made

= Ar of atoms intrested / Mr x100

e.g.

NH4Cl

N% = 14/53.5 x100

N% = 26.2%

moles = mass / Mr

moles = concentration x volume /1000