Chapter 12 Part 2

DO NOW• How have discoveries in

chemistry impacted people’s health and lives?

Lesson 4 – Chemistry and Health (pg 386)

• Alexander Fleming discovered penicillin which led the way to antibiotics. They are used to kill bacteria.

• Vitamins are chemicals that are naturally found in certain foods and prevent many diseases.

• Fertilizers are chemicals used by farmers to help food to grow

Silk is a very nice expensive material

Made from silk worm cocoons

A french scientist made artificial silk

But it easily burst into flames

CHEMISTRY AND NEW MATERIALS (PG. 388)

• Many materials used daily come from nature, but others were created by scientists.

• Scientists worked to create a synthetic replacement for silk and eventually invented polymers. Polymers are large molecules made of identical small units connected together.

• Some useful synthetic materials are plastic and cement.

Where are places we use RUBBER in every day life?

Tires and On the Soles of Shoes

There is NATURAL rubber that comes from Plants!

The PROBLEM with Natural Rubber:

• IT gets GOOEY and MELTY in hot weather!• IT gets BRITTLE and CRACKS in cold weather.

In the 1800’s:

• Scientists experimented with natural rubber and added HEAT and SULFUR.

• This made it more durable!

In the 1900’s

• Chemists developed artificial rubber.

• WHO HAS EVER HEARD OF PETROLEUM?

Petroleum is made up of:

• Gasoline,• Kerosene• Diesel oil• Lubricating oil

• Chemists found a way to separate gasoline molecules from the mixture petroleum!

What does SYNTHETIC mean??

• Hint : – synthesize

Natural Materials? Or synthetic? (What does synthetic mean?)

• Cotton• Wool• Plastic• Nylon• Concrete• Silk

CHEMISTRY and TRANSPORTATION• Rubber for tires!• Petroleum for gasoline!• Mix of metal elements (combined in a factory

or plant) and plastic (made in a lab) for car

Chemistry and New Materials

• Cotton in jeans – natural

• Wool in a sweater– natural

• Nylon in stockings – Made in a lab

• Plastic– Made in a lab

• Concrete– Made in a lab!

Chemicals—Helpful vs Harmful• Chemicals are helpful when used properly!

Chemicals for Cleaning

• Bleach

• Ammonia

• Oven Cleaner

Common chemical bleaches include household chlorine bleach, a solution of approximately 3–6% sodium hypochlorite (NaClO), and oxygen bleach, which contains hydrogen peroxide or a peroxide-releasing compound such as sodium perborate

Care with Chemicals!• READ THE DIRECTIONS!

• Gloves

• Goggles

• Open window• Do not mix without proper knowledge!

– Or else: chemical reactions, lung damage, fumes, burns, explosions, death!

Chemical Warning Labels

How Does temperature affect how long a reaction takes? – alka seltzer lab

MODELS

• Model = – A useful way to understand a subject that you

maybe cannot see or explore in real life• (ex: using magnets to explain what happens in a

chemical reaction)• (ex: a globe to understand what the earth looks like)

Types of Chemical reactions• 1. combination

– Elements or compounds come together to form new compounds

– A + B AB• 2. decomposition

– Compounds split apart to form smaller compounds or elements

– AB A + B• 3. replacement

– Compounds split apart and parts switch places– AB + CD AD + BC