3V les Periodic table and chemical formulas

• Scheikunde
• Middelbare school
• vwo
• Leerjaar 3

Hello 3TVS

Planning for today

- What did we do last time?

- What are we learning this time?

-Theory Calculations and names of molecules

- Time for some homework

- A little bit more theory

- A form to fill in(more information near the end of class)

A break somewhere in between??

Short recap

Who remembers what we learned last week?

The world is built up from molecules and atoms

All types of atoms are found in the periodic table

Molecules are made up from atoms!

But how do we write down what a molecule consists of?

Index and coëfficient

Methane is made up of one Carbon atom and four Hydrogen atoms. Its formula will be:

CH4

The 4 in methane is called an Index

If you have 2 methane molecules, you write it down as:

2 CH4 (and not C2H8)

The 2 before methane is called the coefficient

Index and Coëfficient

The Index denotes how many atoms of one kind are WITHIN a molecule

C2H6

The coëfficient denotes how many molecules are present in a situation

2 HNO3 (Two Nitric acid molecules)

Some practice

What atoms are one water molecule made up from? What is its formula? Does it have an index or coëfficient?

 

What atoms are sugar molecules made up from? What would you write down if you had three sugar molecules?

What atoms are water molecules made up from?

2 Hydrogen atoms, 1 oxygen atom

its formula is H2O
 

What atoms are sugar molecules made up from?

12 Carbon atoms, 22 Hydrogen atoms and 11 Oxygen atoms

If you have three of those molecules you write down:

3 C₁₂H₂₂O₁₁

Time to work

Chapter 2.3, page 58

Make 31, 33, 37, 38, 39, and 40

Want me to discuss any of the questions/topics?

Just a few more things!

Molecules and atoms have mass

We weigh a certain amount, 

because

 the molecules and atoms we are made of weigh a certain amount!

an Atom's mass is indicated in the Periodic table!

One Helium atom

weighs 4,003 u

u stands for Units 

of mass

1 u is equal to 0,000000000000000000000002 grams 

Mass calculation

If water molecules consist of two hydrogen atoms and one oxygen atom they're mass is:

16,00 u + 2 x 1,008 u = 18,016 u

Up next: 

Read "Naming of substances" on page 54

Up next: 

Read "Naming of substances" on page 54

and make 

31, 33, 35, 36, 37, 38, 39, 40, 42, 43, 45

If there is time

The homework is

31, 33, 35, 36, 37, 38, 39, 40, 42, 43, 45

Invulblad!

- Ik vind het zelf niet zulke fijne vragen.

- Het is iets om mee te oefenen

- Ik doe er verder niks mee en het komt niet op het internet.

Regels:

- Doe het in stilte(En wees eerlijk)

- Als je niet wil dat anderen het zien, 

draai je blaadje om of kom hem meteen brengen

- Zodra je klaar bent, mag je hem komen brengen naar mij

- Je mag daarna gaan.