Water (2.2) Flashcards
What kinds of bonds do Hydrogen and oxygen have in water?
Covalent bonds
Why is water a bent molecule?
Because oxygen wants electrons so badly, it tugs electrons toward it in an unequal sharing of electrons. This gives O a negative charge and H a positive charge. (polar covalent bond)
What are hydrogen bonds?
Hydrogen bonds are weak intermolecular forces, which give water its unique properties.
How many electrons does oxygen have?
6
How many electrons does hydrogen have?
1
What causes a polar covalent bond?
this forms from the uneven sharing of electrons
How do hydrogen bonds form?
They form when the negatively charged oxygen on one molecule is electrostatically attracted to the positive hydrogen on another
What are the 4 properties of water?
Cohesive, adhesive, thermal, and solvent
What is dipolarity?
Having different charges in one molecule
What is cohesion?
Cohesion refers to the binding of 2 molecules of the same type
Why does water cohere?
Water coheres because of hydrogen bonds
What is transpiration?
The evaporative loss of water from plant leaves
What is adhesion?
Adhesion refers to the binding of water to another polar molecule
What is capillary action?
the ability for a liquid to flow through narrow spaces without the assistance of gravity
How does water’s cohesion properties support life?
- it allows water to be transported to the top of trees through xylem vessels
How does water’s adhesion support life?
- in leaves, water adheres to cellulose in the cell wall f leaves
- aids in drawing water up during capillary action
Thermal properties of water
high specific heat capacity, high heat of vaporization, water as a coolant, and high boiling point
What causes a high specific heat capacity in water?
H-bonds restrict water’s movement, which causes water to need a large amount of energy to change temperature. Water can absorb or lose great amounts of energy while keeping a stable temperature.
How does high specific heat capacity in water support life?
- aquatic organisms can maintain homeostasis due to the stable temperatures of water.
What causes water’s high heat of vaporization?
Water needs a large amount of energy to evaporate because H-bonds need to be broken.
What causes water’s coolant properties?
Evaporation has a cooling effect. When a molecule evaporates, it takes a small amount of heat with it.
How does water’s coolant properties support life?
- evaporating sweat helps humans maintain a steady body temperature.
What are water’s boiling and freezing points?
100 C and 0 C. This is the temperature range for most organisms on Earth
What are water’s solvent properties?
Many different substances can dissolve in water because of it’s polarity (ex. Na and glucose)
