Unit 1: Stoichiometric Relationships

Do Now 9/14/15 – 5 min The lengths of the sides of a wooden block are measured and the diagram shows the measured values with their uncertainties.

1. What is the percentage and absolute uncertainty in the calculated area of the block?

40.0 ± 0.5 mm

20.0 ± 0.5 mm

Topics in this unit: Atomic theory, states of matter, elements and compounds, writing

balanced reactions, SI units, the mole, empirical formulas, stoichiometry, limiting reactant, concentrations of solutions, gas laws, titrations

Recommended time on this unit from IB: 13.5 hours????

We spent a whole month on stoichiometry/limiting reactants last year

A week on titrations

A week on reading/balancing reactions

A week on the mole

Week on solutions

2 days on states of matter

1 day on elements vs compounds

Didn’t cover gas laws at all….

You will have to read on your own. Make sure you are coming in right away as questions occur.

SI Units

Property Unit Symbol

mass kilogram kg

temperature kelvin K

time second s

amount mole mol

electric current ampère A

length metre (meter) m

luminosity candela cd

All other units are derived from these units other prefixes (nano, milli, centi, deci, etc)

As we discussed the common IB unit of volume is dm3 which is = to 1L

Matter Types of Matter

Element- contains elements of only one type

Compounds – atoms of elements combined in a fixed ration and are made of molecules or ions.

Mixtures – Two substances combined physically Can be separated physically (distillation,

chromatography, magnets, flitration…etc)

Homogeneous –uniform composition (salt water, metal alloys)

Heterogeneous – non-uniform composition (salad dressing, garden soil)

Matter Phases of Matter – read about change of state pg 3-4

Solid Fixed volume and shape

Cannot be compressed

Closely packed, vibrate in place

Liquid Fixed volume, no fixed shape

Cannot be compressed

Close together, but forces weaker than those in solids

Particles move around

Gas No fixed volume or shape

Can be compressed

Partiles far apart, move around more than in liquids

Language of Chemistry(read TOK on page 7)

Chemical symbols – IUPAC (international union of pure and applied chemistry) monitors systematic naming of elements and compounds. No translation is needed from country to country.

Balanced chemical equations use arrows and phase labels

Reactants Products

2 HCl (aq) + Mg (s) MgCl2 (aq) + H2 (g)

Common combinations of Elements Ions are charged particles

Some ions are formed by neutral elements gaining or losing electrons (in very predictable patterns)

Some ions are polyatomic ions see Table 1 on pg 7.

Some elements are diatomic N2, O2, F2, Cl2, Br2, I2, H2

Others are Different as well

Common S8, P4

Monatomic ions Look at bohr models

Atoms are stabalied full outer shell Either cation: lose all outer electrons for full previous shell (+

ion)

OR anioin: gain enough electrons to fill current outer shell (- ion)

Balance Reactions Mass should be equal before and after reaction.

Coefficients represent ratios of #s of particles (or moles of particles) NOT mass ratio

Examples:

Chlorine gas reacts with solid calcium to produce solid calcium chloride.

Solid magnesium reacts with aqueous hydrochloric acid to form aqueous magnesium chloride and hydrogen gas.

Types of Reactions

Read about types of reaction on page 9

Practice problems 20-27 in summer homework (part b)

Experimental empirical and molecular formla

Homework tonight: Read page 14-19

Complete question 9 on page 35

Read lab for tomorrow