Study Questions #1: Water

Question 1

What is the fundamental reason for all the remarkable properties of water?

Answer 1

Hydrogen Bonding

- water is polar, and charged, and hydrophilic

Question 2

What is the difference between cohesion and adhesion?

Answer 2

Cohesion: water clings to water
Adhesion: water clings to other polar molecules

*water attracted to anything with a charge

Question 3

Why does water have such high specific heat and such high heat of vaporization?

Answer 3

Need to first break hydrogen bonds then molecules move faster
- heat from stove breaks hydrogen bonds allowing molecules to speed up

Question 4

Why should you use deodorants rather than anti-antiperspirants?

Answer 4

Sweating decreases body temperature

Antiperspirants trap heat under the skin, stopping the sweating.

Question 5

Why does it float?

Answer 5

When forming a solid, water molecules produce a very precise array.
Water molecules are farther apart when in liquid form; less dense

Question 6

Why is water such a good solvent?

Answer 6

Water forms hydration shells around polar molecules or ions.

Solvent: part of a solution in greater quantity

Question 7

Why are ionic bonds weaker in water?

Answer 7

Water is between the ions

Question 8

What is the difference between the mean and the median?

Answer 8

mean: average
median: central value when numbers are in increasing order

Question 9

Why is the median often used instead of the mean?

Answer 9

better measure of central tendency

Question 10

What is the standard deviation, and how does it differ from the variance?

Answer 10

Standard deviation = sq rt. variance

denotes degree to which each value deviates from the mean

Question 11

What is a statistical test, and what are they used for?

Answer 11

When testing a hypothesis, observed data is compared to expected data in order to analyze the data
- particular forms are used

Ex: chi-square (dice)
t-test (height)