Week 7 - Covalent Bonds, Chemical Indicator, pH

Question 1

Valence electrons

Answer 1

Electrons in the outermost shell of an atom

Question 2

Formed when one atom accepts or donates one or more of its valence electrons to another atom

Combination of ions.

Requires one positive ion (cation) one negative ion (anion).

Answer 2

Ionic bond

Question 3

Metal (cation) + nonmetal (anion) =

Answer 3

Ionic bond

Question 4

Ionic bond compounds

Answer 4

Electrolytes

Question 5

Occurs when two or more nonmetal atoms co e together and share valence electrons to become stable.

Answer 5

Covalent bonds

Question 6

Do covalent bonds break in water?

Answer 6

No. Covalent bonds are strong

Question 7

Compounds containing covalent bonds are

Answer 7

Nonelectrolytes

Question 8

Have lower melting and boiling points than ionic compounds

Answer 8

Covalent molecules

Question 9

One pair of electron is shared between atoms

Bond can be represented by a single line or dash

Lewis dot structure.

Answer 9

Single covalent bond

Question 10

Two pairs of electrons (4) bring shared.

Represented by a double line.

Answer 10

Double covalent bond

Question 11

Sharing 3 pairs of electrons (6).

Answer 11

Triple covalent bond

Question 12

Depends on the electronegativity of the atoms involved

Answer 12

Polarity

Question 13

Attraction of an atom for electrons in a covalent bond

Answer 13

Electronegativity

Question 14

Two atoms with the same electronegativity will share the bonding electron pairs equally

No separation of charges

Answer 14

Nonpolar covalent bond

Question 15

Two bonded atoms have different electronegativity, the bonding pairs of electrons will be shared unequally

Answer 15

Polar covalent bonds

Question 16

Any substance that gives a visible sign, usually by a colour change, of presence or absence of a threshold concentration of a chemical, such as an acid or an alkali in a solution is called:

Answer 16

Chemical indicator

Question 17

Qualities of chemical indicators are:

Answer 17

Must be both sensitive and easily detectable

Doesn’t change the conditions of the sample

Question 18

This indicator is either a weak acid or a weak base that exhibits a colour change as the concentration of hydrogen (H+)/ or hydroxide (OH-) ions changes in an aqueous solution:

Answer 18

Acid-Base indicator

Question 19

Use of acid-base indicators

Answer 19

In titration to identify the endpoint of an acid-bade reaction

Gauge pH values

Question 20

Change colour in response to different pH values

Litmus paper and pH paper are used for quick and relatively imprecise measurements

Strips of paper that have been treated with this :

Answer 20

Acid-Base indicators

Question 21

A logarithmic measure of the hydrogen ion concentration of an aqueous solution (pH=-log[H+]) is referred to as:

Answer 21

pH

Question 22

pH below 7 is:

Answer 22

Acidic

Question 23

pH greater than 7 is:

Answer 23

Basic

Question 24

Very strong acids may have a

Answer 24

Negative pH

Question 25

Very strong bases may have a

Answer 25

pH exceeding 14

Question 26

Change colour over a narrow range of pH values solution Display different colours between certain pH limits

Answer 26

pH indicator

Question 27

Normal pH range for blood

Answer 27

Between 7.35 and 7.45

Question 28

The glomerular filtrate of blood is usually acidified by the kidneys from a pH of approximately ___ to a pH of _ in the urine

Answer 28

7.4 and 6

Question 29

The pH of urine may range from

Answer 29

4.5 to 8

Question 30

Done by measuring different buffer solutions with standardized values Using buffers with pH 4 and 10 pH meter is adjusted based on any deviations from the buffer’s known pH value

Answer 30

Calibration

Question 31

A minimum of three standards are require for a calibration curve

Answer 31

Best accuracy

Question 32

Patient samples have different values and biological characteristics

Answer 32

Sample differences

Question 33

As the ________, water ionize and form more ______.

Answer 33

Temperature rises and hydrogen ions