Ch. 2.2 Properties of Water

​2.2 Properties of Water

​Why is water vital to life?

E. Explain the unique qualities of water.

• I can define the term​s adhesion and cohesion

• I can explain polarity in water molecules as it relates to hydrogen bonds

• I can explain why hydrogen bonds are essential to living things

• I can explain the importance of heat capacity of water

• I can explain why water is essential to life​

2.2​

​The Water Molecule

​Polarity

• Oxygen in water attracts more electrons than the hydrogens.

• Why?

  • How many protons does oxygen have? ________

  • Ho​w many protons does hydrogen have? ________

  • Where will the electrons be more likely to be found?

2.2​

​The Water Molecule

​Polarity

• What is the result?

  • This makes oxygen slightly more _____________

  • This makes hydrogen slightly more ____________

  • Therefore the charges are unequally distributed and the molecule is said to be _______________.

2.2​

​The Water Molecule

​Polarity

• Why is this important?

  • Polar molecules attract each other.

  • The attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge is known as a hydrogen bond

2.2​

​The Water Molecule

​Special Properties of Water

• Cohesion:

  • attraction of molecules of the same substance

  • water molecules drawn together

  • drops of water on a smooth surface- water beads on your car

  • surface tension- allows bugs to walk on water​

2.2​

​The Water Molecule

​Special Properties of Water

• Adhesion:

  • attraction of molecules of different substances

  • capillary action: water drawn up in a hollow tube against gravity

  • capillary action allows plants to draw water from the roots to the stems and leaves

2.2​

​The Water Molecule

​Special Properties of Water

• Heat Capacity:

  • amount of energy needed to raise the temperature of a substance by making its molecules move faster

  • large bodies of water absorb large amounts of heat with only a small change in temperature

2.2​

​The Water Molecule

​Special Properties of Water

• Heat Capacity cont

  • reduces drastic changes in water temperature

  • coastal climates moderated

    ​

2.2​

​The Water Molecule

​Special Properties of Water

• Why water is essential to life

  • 60 percent of the mass of the human body is water

  • nearly all chemical reactions take place in water

  • We need water to breath- without it diffusion of oxygen does not happen

  • We also need water to cool our bodies and remove wastes

2.2​

Multiple Choice

Water beading on the hood of a car is an example of

• Cohesion

• Adhesion

Multiple Choice

The oxygen part of water is slightly _______; the hydrogen part of water is slightly _______.

• positive, negative

• negative, positive

Multiple Choice

As a result of the slight charge differences water is a _______ molecule.

• covalent

• ionic

• polar

• non-polar