ch.2 properties of water

Question 1

water is more dense in a ___

Answer 1

liquid form

Question 2

temperature is a measure of how _____

Answer 2

rapidly its individual molecules are moving

Question 3

specific heat measures ____

Answer 3

the extent to which a substance resists changing its temperature when it absorbs or loses heat.

-polar substances tend to form hydrogen bonds, the more polar it is, the higher is its specific heat.

Question 4

PH scale is a more _____

Answer 4

convenient way to express the hydrogen ion concentration of a solution.

-The scale defined pH which stands for “power of hydrogen” and the negative logarithm of the hydrogen ion concentration.

Question 5

acid is a substance that _____

Answer 5

-any substance dissociates in water to increase the [H+] (and lower the pH) is called an acid. the stronger the acid is, the more hydrogen ions in produces and the lower its pH.

Question 6

Base is a substance that ____

Answer 6

combined with H+ when dissolved in water and thus lowers the [H+].

Question 7

are pH and H+ directly proportional or inversely proportional?

Answer 7

inversely proportional– as H+ gets higher, pH gets lower and the reverse.

Question 8

pH inside almost all living cells is___

Answer 8

fairly close to neutral, 7.

Question 9

what is pH?

Answer 9

unit of measurement and stands for potential hydrogen– tells us how much hydrogen is in a liquid and how active the hydrogen is.

Question 10

buffer

Answer 10

=is a substance that resists change in pH.
-releasing hydrogen ions when a base is added and absorbing hydrogen ions when acid is added, with the effect of keeping H+ relatively constant.

-consists of pairs of substances, one an acid and the other a base.

Question 11

acid vs base

Answer 11

acid:
-pH value lower than 7
-when dissolved in water gives H+ ions
-sour

base:
-bitter
pH value higher than 7
-when dissolved in water gives hydroxide ions (OH- ions)