Unit 1: Chemistry of Life

Question 1

Together, just four elements make up more than 95 percent of the body’s mass. These include:

Answer 1

Oxygen, carbon, hydrogen, nitrogen

Question 2

The smallest unit of an element that still retains the distinctive behaviour of that element is an:

Answer 2

Atom

Question 3

The characteristic that gives an element its distinctive properties is its number of:

Answer 3

Protons

Question 4

On the periodic table, the number reported as the atomic mass is typically the “average atomic mass” of all naturally occurring isotopes, and considers the relative abundances of each isotope. On the periodic table of elements, mercury (Hg) has an atomic number of 80 and an atomic mass number of 200.59. Hg has seven stable isotopes. The most abundant atoms of Hg probably have:

Answer 4

More than 80 neutrons each

Question 5

Protium, (hydrogen isotope), has a mass number of one. This means that it has:

Answer 5

One proton, no neutrons, and one electron

Question 6

Oxygen has an atomic number of 8. How many electron shells does it likely have:

Answer 6

2

Question 7

A molecule of ammonia contains one atom of nitrogen and three atoms of hydrogen. These are linked with______?

Answer 7

Polar covalent bonds

Question 8

When a neutral atom, like sodium (Na) donates an electron to another atom, it becomes:

Answer 8

An ion

Question 9

A substance formed of crystals of equal numbers of anions and cations held together by ionic bonds is called a(n)?

Answer 9

Salt

Question 10

Na(+) + Cl(-) -> NaCl is an example of a(n) _________ reaction?

Answer 10

Synthesis

Question 11

_________ reactions release energy.

Answer 11

Exergonic

Question 12

Which of the following combinations of atoms is MOST likely to result in a chemical reaction?
Hydrogen + Helium
Hydrogen + Hydrogen
Neon + Oxygen
Helium + Oxygen

Answer 12

Hydrogen + Hydrogen

Question 13

CH4 is methane. This compound is ________.

Answer 13

Organic

Question 14

A liquid medication that appears homogenous at first, starts to separate after a few minutes. This type of liquid is a _________.

Answer 14

Suspension

Question 15

Energy that is transmitted as waves, including microwaves, is which type of energy?

Answer 15

Radiant

Question 16

Which of the following correctly orders items from lowest pH to highest?
1) hydrochloric acid, blood, ammonia
2) blood, baking soda, pure water
3) saliva, coffee, lemon juice
4) pure water, bleach, urine

Answer 16

1) hydrochloric acid, blood, ammonia

Question 17

What is TRUE about acids?
1) It has a pH of 7 or higher
2) It accepts H(+) in a solution
3) It increases the concentration of H(+) in an aqueous solution
4) It releases OH(-) into a solution

Answer 17

3) It increases the concentration of H(+) in an aqueous solution

Question 18

Which of the following is FALSE about blood pH?
1) It normally ranges from 7.35 to 7.45
2) In normal circumstances, it is slightly alkaline
3) It can be regulated by several means, including chemical buffer systems
4) The body can tolerate a wide range of pH

Answer 18

4) The body can tolerate a wide range of pH

Question 19

In a dehydration reaction:

Answer 19

A new product is synthesized and molecule of water is released as a by product

Question 20

What are Ionic Bonds?

Answer 20

Close association between ions of opposite charge.
Cation is +
Anion is -

Question 21

What are Covalent Bonds?

Answer 21

They share electrons in a mutually stabilizing way.
Polar: extremes, positives and negatives
Nonpolar: not charged, no negatives or positives

Question 22

What are Hydrogen bonds?

Answer 22

Formed when a weakly positive hydrogen atom already bonded to one electronegative atom (Oxygen in water to another electronegative atom from another molecule)

Question 23

What are some examples of form of energy we use?

Answer 23

Kinestic, potential, gravitational, chemical, mechanical, electrical

Question 24

What is a synthesis reaction?

Answer 24

A + B = AB

Question 25

What is a decomposition reaction?

Answer 25

AB = A + B

Question 26

What is an exchange reaction?

Answer 26

AB + CD = AD + BC

Question 27

What factors can influence the rate of a reaction?

Answer 27

Surface area, reactivity, temperature, concentration, enzymes or catalysts

Question 28

What are enzymes?

Answer 28

A control system for enzymatic activity in which enzymes are turned “on” or “off” depending on the organism’s needs; decrease the activation energy needed for a chemical reaction to occur.