I. The Water Molecule Water has a partial negative charge at one end, and partial positive charge on the other. Water has a partial negative charge at.

I. The Water MoleculeI. The Water Molecule

• Water has a partial Water has a partial negative charge at negative charge at one end, and partial one end, and partial positive charge on positive charge on the other.the other.

• Molecules with Molecules with charges that are not charges that are not distributed evenly distributed evenly are “polar” are “polar”

I. The Water MoleculeI. The Water Molecule

• Hydrogen bondingHydrogen bonding– Is the attraction between Is the attraction between

a hydrogen atom with a a hydrogen atom with a partial positive charge partial positive charge and another atom with a and another atom with a partial negative charge. partial negative charge. • Hydrogen bonds are not as Hydrogen bonds are not as

strong as covalent or ionic strong as covalent or ionic bonds.bonds.

• Water is able to form Water is able to form multiple hydrogen bonds.multiple hydrogen bonds.

I. The Water MoleculeI. The Water Molecule

• CohesionCohesion i is an s an attraction between attraction between molecules of the molecules of the same substancesame substance– It causes water It causes water

molecules to be molecules to be drawn together, drawn together, which is why drops which is why drops of water form beads of water form beads on a smooth surface.on a smooth surface.

I. The Water MoleculeI. The Water Molecule

• AdhesionAdhesion is an is an attraction between attraction between molecules of the molecules of the different different substances.substances.– Is responsible for Is responsible for

causing water in causing water in glass columns to glass columns to riserise..

I. The Water MoleculeI. The Water Molecule

• Heat capacityHeat capacity is the is the amount of heat energy amount of heat energy that is required to that is required to increase the increase the temperature of a temperature of a substance.substance.– Multiple bonds in water Multiple bonds in water

molecules requires a molecules requires a large amount of heat large amount of heat energy to cause those energy to cause those molecules to move molecules to move faster.faster.

II. Solutions and II. Solutions and SuspensionsSuspensions

• A mixture is a material that is A mixture is a material that is composed of two or more elements composed of two or more elements or compounds that are physically, or compounds that are physically, but not chemically combined.but not chemically combined.– The two types of mixtures are solutions The two types of mixtures are solutions

and suspensions.and suspensions.– Living things are composed of mixtures Living things are composed of mixtures

water water

SolutionsSolutions

• Are mixtures in which Are mixtures in which the components are the components are evenly distributed evenly distributed throughoutthroughout– The components of The components of

mixtures are a:mixtures are a:• Solute which is the Solute which is the

substance that is substance that is dissolved.dissolved.

• Solvent which is the Solvent which is the substance that substance that dissolves the solute.dissolves the solute.

SolutionsSolutions

•Water dissolves salts, sugars, Water dissolves salts, sugars, minerals, gases and other minerals, gases and other solvents like alcohol.solvents like alcohol.

•Water is the greatest solvent on Water is the greatest solvent on Earth.Earth.

Suspensions

•Are mixtures of water that have undissolved materials.

•Some materials do not dissolve when placed in water.

•Blood contains undissolved particles that remain suspended as blood moves through the body.

III. Acids, bases, and pHAcids are substances that:

Hydrochloric acid is a strong acid.

Acetic acid (vinegar) is a weak acid.

have a pH below 7 and turns universal indicator paper yellow, orange or red

form solutions containing hydrogen ions (H+).

III. Acids, bases, pH

• Bases are compounds that produce Hydroxyl (OH-) ions in solution.

• Examples are oven cleaners and bleach

III. Acids, bases, and pH

•The pH scale– Is a measurement system that is used to

indicate the concentration of hydrogen (H+) ions in solution.•The pH scale ranges from 0-14.

– Solutions with a pH below 7 are acidic.– Solutions with a pH above 7 are basic.

•Each step on the pH scale represents a factor of 10.

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What is the order of pH?

IV. Buffers

• Are weak acids or bases that can react with strong acids or bases to prevent sharp or sudden changes in pH.

• Are dissolved in life fluids to maintain homeostasis in organisms.