Chemistry of Living ThingsChemistry of Living ThingsProperties of WaterProperties of Water

Properties of Water

• Water: H2O

• Polar molecule due to its shape and uneven distribution of electrons

• Polar: having a + and - side

Properties of Water• Oppositely charged

ends attract forming hydrogen bonds

• Waters polarity produces Cohesion and Adhesion

Properties of Water

• Cohesion: Water sticking to itself

• Adhesion: water sticking to other things

MIXTURESMIXTURES• Water is not always pure. It is often Water is not always pure. It is often

found as part of a mixture. found as part of a mixture.

• A mixture is a material composed of A mixture is a material composed of TWO OR MORE ELEMENTS OR TWO OR MORE ELEMENTS OR COMPOUNDS THAT ARE COMPOUNDS THAT ARE PHYSICALLY MIXEDPHYSICALLY MIXED– Ex: salt & pepper mixed, sugar and sand – Ex: salt & pepper mixed, sugar and sand –

can be easily separatedcan be easily separated

SOLUTIONSOLUTIONTwo parts:Two parts:• SOLUTE:SOLUTE: The substance being dissolved The substance being dissolved• SOLVENTSOLVENT - the substance in which the - the substance in which the

substance dissolves substance dissolves • Solutions are Solutions are HOMOGENEOUSHOMOGENEOUS (same (same

throughout)throughout) Ex. Salt WaterEx. Salt Water• SUSPENSIONS:SUSPENSIONS: a mixture in which a mixture in which

undisolved materials are so small they are undisolved materials are so small they are suspended(floating)suspended(floating)– Blood is the most common example of a Blood is the most common example of a

suspension. suspension. – Cells & other particles remain in suspension.Cells & other particles remain in suspension.

Acids, Bases and PHAcids, Bases and PH

Acids and BasesAcids and Bases

• Water molecules react forming ions

• H2OH+(hydrogen) + OH-(Hydroxide)

• So what is PH???• PH: The hydrogen Ion

concentration, acidic or basic

pH SCALEpH SCALE

• measures the degree measures the degree of alkalinity(basic) or of alkalinity(basic) or acidityacidity

• Ranges from Ranges from 0 to 140 to 14

• 0 – 6 acidic0 – 6 acidic

• 7 neutral7 neutral

• 8-14 basic8-14 basic

Measuring PH

• Litmus paper: Acid turns litmus red and Base turns litmus Blue

• Wide range Ph paper: tells the exact ph using a color scale