Chemistry of Water

Question 1

What kind of bond is better individual atoms within H2O?

Answer 1

Polar Covalent Bonds

Question 2

What kind of bond is between H2O molecules?

Answer 2

Hydrogen bonds

Question 3

Cohesion

Answer 3

attraction between water because of hydrogen bonds (water sticking to itself ; same substance)

Question 4

Adhesion

Answer 4

Attraction of hydrogen bond and other charged molecules (between two chargers molecules ; different substances)

Question 5

Capillarity

Answer 5

combination of cohesion and adhesion resulting in rise of surface in tube; (water sticking to itself) + (attraction between charged molecules) = upward movement against gravity

Question 6

Water vs Metal experiment results

Answer 6

• water cooled the slowest > requiring more heat energy than metal
• hydrogen bonds require a lot of heat to be broken&raquo_space; water helps stabilize temperature

Question 7

Evaporating Water experiment results

Answer 7

takes more energy to evaporate water than to boil water

Question 8

method to calculate calories

Answer 8

1) how much heat energy left the hot plate into evaporating beaker (B) by recording temperature change in Beaker A (same time)
2) how many total calories recorded by heat meter (starting to boil in beaker C)
3) finding head energy required for 1mL

Question 9

formula to calculate calories

Answer 9

1) starting temp-temp starting to boil =
change in temperature
2) change in temp x 100 = calories to boil
3) total cal / total mL = cal/mL

Question 10

pH

Answer 10

Potential Hydrogen (Ions)
- goes up by factors of 10
- ph = 7 : Neutral, H+ and OH- are equal and balanced

Question 11

Buffer

Answer 11

chemical substance than can be added to a solution which can resist a pH change

Question 12

Light vs. Heavy Molecules

Answer 12

smaller molecular weight can pass through quick