ELEMENTELEMENT

hydrogen molecule, H2

ELEMENTELEMENT

oxygen molecule, O2

MIXTUREMIXTURE

a mixture ofhydrogen and oxygen molecules

CHEMICAL REACTIONCHEMICAL REACTION

if molecules collide with enoughforce to break them into atoms, a can take place

COMPOUNDCOMPOUND

water, H2O

2 H22 H2 O2

O2 2 H2O2 H2O++ ++ EE

Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

The Zeppelin LZ 129 Hindenburg catching fire on May 6, 1937 at Lakehurst Naval Air Station in New Jersey.

S.S. Hindenburg

35 people died when the Hindenburg exploded.

May 1937 at Lakehurst, New Jersey

• German zeppelin luxury liner

• Exploded on maiden voyage

• Filled with hydrogen gas

Hydrogen is the most effective buoyant gas,but is it highly flammable. The disastrous fire in the Hindenburg, a hydrogen-filled dirigible, in 1937 led to the replacement of hydrogen by nonflammable helium.

Erosion Takes a Powder

TreatedUntreated

Top soil r

unoff

Sodium Polyacrylate

• Absorbent Material– Absorbs 700x volume of water

• Magicians– Pour water in hat and it “disappears”

• Diapers• Farmers

– Anti-erosion powder

• Add to Soils– hold moisture between watering

Specific Heats of Some Substances

Specific Heat

Substance (cal/ g oC) (J/g oC)

Water 1.00 4.18Alcohol 0.58 2.4Wood 0.42 1.8Aluminum 0.22 0.90Sand 0.19 0.79Iron 0.11 0.46Copper 0.093 0.39Silver 0.057 0.24Gold 0.031 0.13