Chemistry
The type of weak bond that forms BETWEEN two individual water molecules
HYDROGEN BOND
Which property of water describes its ability to form bonds with other water molecules?
COHESION
pH = 10 would be considered a ___________.
BASE
Water is less dense as a solid (ice). What is the Ecological significance of this property??
Solid ice floats on top of liquid water, insulating the water beneath to allow for some aquatic life to survive the winter AND solid ice provides a habitat for organisms above water!
Which SIX elements make up ALL LIVING THINGS?
CHNOPS or SPONCH (carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur).
Type of strong bond that forms between slightly positive (H) and slightly negative (O) WITHIN a molecule of water.
POLAR COVALENT BOND
Which property of water accounts for stronger hydrogen bonding towards the surface of a body of water?
HIGH SURFACE TENSION
ACIDIC solutions contain many _____ ions, whereas BASIC solutions contain many ____ ions.
ACIDIC = H+ (protons) ; BASIC = OH- (hydroxide)
What is the Ecological significance of water's high SURFACE TENSION?
Stronger bonds between water molecules at the surface of a body of water allow for life forms to skate across the surface without sinking/ drowning. (Water strider insects, Jesus lizard, etc).
What is a TRACE ELEMENT?
An element required for standard bodily functions and development in VERY SMALL quantities (Calcium, Zinc, Magnesium, etc)
Methane, CH4 is NONPOLAR, whereas individual O-H bonds in water are POLAR. How does ELECTRONEGATIVITY explain this difference?
NONPOLAR molecules = equal sharing of electrons throughout. POLAR molecules = unequal sharing of electrons ... Oxygen is MORE ELECTRONEGATIVE than Hydrogen in water.
"A watched pot never boils." Which property of water is responsible for your pasta water taking forever to reach its boiling point?
HIGH SPECIFIC HEAT CAPACITY
Using a red cabbage indicator solution, what COLOR CHANGE would you expect to see after adding cabbage solution to Vinegar? (pH = 3)
PINK
How does water's high specific heat capacity regulate Earth's global temperatures?
Water can absorb A LOT of energy (heat/ solar) before its temperature increases significantly. This allows for large bodies of water to absorb large amounts of solar energy, keeping temperatures cool around oceans, ponds, etc.
Think: Earth's surface is ~70% water!!
All ACIDS have a chemical structure that acts as an "acidic group." What is it?
"COOH"
Which subatomic particle determines the IDENTITY OF AN ELEMENT?
Why can water dissolve many IONIC substances and other POLAR substances?
WATER IS A GOOD SOLVENT. Because water is POLAR!! Ionic (charged) substances can interact with the partial positive region of water to dissolve, other POLAR substances interact with both regions to dissolve. Water CANNOT dissolve non-polar substances.
The pH scale is a logarithmic measurement of H+ ions in solution. Each whole number increase along the scale represents a _______x change in H+ ions.
10x
How can chemical tracers such as Carbon-14 be used to enhance scientific research?
Radioactive isotopes (such as carbon-14) can act as fluorescent tracers that are visually tracked throughout a patient/ subjects body during testing / examination
Predict what would happen to CAPILLARY ACTION if water molecules still adhered to the tube walls inside plants but had MUCH WEAKER ATTRACTION to other water molecules.
REDUCED COHESIVE FORCES. Water would be unable to "move up" the veins inside plants without cohesion, meaning the plant would die.
Carbon-14 is an example of a ___________________. What makes it different from standard Carbon?
RADIOACTIVE ISOTOPE. Different # of neutrons in the atom's nucleus.
When liquid water freezes, bonds between separate water molecules spread out, forming a chemical pattern called a __________________.
Occasionally, attraction between water molecules and presence of free (H+) ions in solution can cause the formation of ________.
HYDRONIUM (H3O+)
What is Ocean Acidification? What are its ecological implications?
Global CO2 emissions are increasing. Atmospheric CO2 is absorbed by our oceans (and other large bodies of water) producing CARBONIC ACID, lowering overall pH of the ocean. This reaction (and decrease in pH) makes it SIGNIFICANTLY harder for marine organisms to build shells, for coral reefs to thrive, etc.
Solution (A) has a pH = 6. Solution (B) has a pH = 4. How many times greater is the H+ concentration in solution (B)?
100x GREATER. pH is a LOGARITHMIC measurement of H+