John Dalton(6 september 1766 – 27 juli 1844)

was een Brits scheikundige en natuurkundige.

Atoms

Atoms(3min)

• Atom has • diameter from circa 60 pm (helium) until

275 pm (francium) . p (pico) = x 10-12

• Exists of:

– a nucleusDiameter ≈ 10-14 meter.

–Electron cloud. Electrons rotates around the nucleus.

Atom

• There are more than 117 different atoms.

Periodic table

Molecuul

• Is the smallest part of a substance that has still the substance characteristics.

• A molecule is builde out of 1 or more atoms:– H2O Water– CO2 Carbondioxide– O2 oxygen

Molecule

Also sugar contains out of moleculesHow big are molecules?

You can’t see them.

Even not with a normal microscope

A sugar molecule is about0,000001 mm (1 x big

When you change the molecules form 1 cm³ sugar

into sand, Holland will be covert with 10 m sand.

Molecule

Molecuul model

• It’s describes the properties of a molecule.

There are six important properties

Molecule model / particle model

Molecule-model

1Each substance

has his own molecule.

2Molecules are

moving.

3There is space

between molecules

4In a solid the

molecules are moving around a

fixed position

5Molecules are moving faster

when the temperature

rises

6Molecules are attracting each

other.

Molecule model / particle model

• Each substance contains there own kind of molecules

That's why each substance has his own properties

Assumption 1

Molecules are moving

Higher the temperature:

Faster movement.Greater distance between molecule.Substance expands.

(the number of molecules stay the same)

Assumption 2

There is space between the molecules

one litre alcohol mixed with one litre water gives les then 2 litre.

250 mL tea with 25 mL sugar gives les then 275 mL mixture.

Veronderstelling 3Assumption 3

In a solid are the molecules moving around a fixed position

In a liquid and gas are the molecules moving freely

Veronderstelling 4Assumption 4

Molecules are moving faster when the temperature rises.Result:

Moe movement more space.More space -> expansionLes force between the molecules.

Assumption 5

Molecules attracts each other.

• There are two kinds of attraction:1. Cohesion

Force between the same molecules

2. AdhesionForce between different kind of molecules.

Veronderstelling 6Assumption 6

Cohesion

Adhesion

6: Keywords

• Cohesion = Force between the same kind of molecules.

• Adhesion = Force between the different kind of molecules.

• Capillary = Very thin tube or channels in in papier.

• Capillary function = When a liquid rices in a thin tube.

• Meniscus = The surface of a fluid.

“Als je een suikerklontje in een glas koud water houdt, zuigt het water op. In een glas hete thee gaat dat opzuigen veel sneller”

Verklaar a.d.h.v. het molecuulmodel

Voorbeeldvraag: