Water, carbon and more

Question 1

What is chemical evolution?

Answer 1

Chemical Evolution is the theory that simple chemical compounds in the ancient atomsphere and ocean combined via spontaneous chemical reactions to form larger, more complex substances - eventually leading to the origin of life and the start of biological evolution

Question 2

What i the most common molecule found in natural gas?

Answer 2

Methane (CH4)

Question 3

What happens when a chemical reaction occurs?

Answer 3

When a chemical reaction occurs, one substance is combined with others or broken down into another substance. Atoms are rearranged in molecules; in most cases, chemical bonds are broken and new bonds form

Question 4

What is the molecular weight?

Answer 4

The molecular weight is the sum of the mass numbers of all the atoms in the molecule.

Question 5

What is molarity?

Answer 5

The number of moles of the substance present per liter of solution.

Question 6

How many covalent bonds can Carbon form?

Answer 6

A carbon atom can form a total of four covalent bonds because there are four unpaired electrons in its valence shell

Question 7

What is a primary reason for which water is vital?

Answer 7

Water is an excellent solvent - an agent that dissolves substances into a solution.

Question 8

What is the hydrogen bond?

Answer 8

The hydrogen bond is a weak interaction between two molecules or different parts of the same molecule that results from the attraction between a hydrogen atom with a partial positive charge and another atom (usually O or N) with a partial negative charge

Question 9

What are hydrophilic substances?

Answer 9

Hydrophilic substances are ions and polar molecules that stay in a solution because of their interactions with water’s partial charges. These attractions are said to be hydrophilic or “water loving”

Question 10

What are hydrophobic substances?

Answer 10

Hydrophobic substances are compounds that are uncharged and non-polar that do not interact with water through hydrogen bonding.

Question 11

How does water’s structure correlate with its properties?

Answer 11

Water’s small size, bent shape, highly polar covalent bonds, and overall polarity is unique among molecules. This structure causes properties such as cohesion, adhesion and surface tension.

Question 12

What is cohesion?

Answer 12

Binding between like molecules

Water is cohesive, which means that the water molecules cling to each other due to attractive forces.

Question 13

What is adhesion?

Answer 13

Binding between unlike molecules

Water is adhesive because it adheres to surfaces that have any polar or charged components

Question 14

What is an example of cohesion and adhesion in plant biology?

Answer 14

Cohesion and adhesion explain how water moves from the roots of plants to their leaves.

Question 15

What is another real life example of daily cohesion and adhesion?

Answer 15

A meniscus forms in a glass of water as a result of two forces:

1. Water molecules at the surface hydrogen bond (cohesion) with the molecules below them, so they experience a net downward pool.
2. Water molecules at the surface also adhere to the glass, allowing them to resist the downward pull. (adhesion)

Question 16

What role does cohesion play in surface tension?

Answer 16

Cohesion is instrumental in surface tension, because hydrogen bonding exerts a pulling force (tension) at the surface of any body of water, the water molecules are not stable. This means they are constantly being pulled away from the surface. The body of water is most stable when the surface area is minimized.

Water resists any force that increases its surface area, making a water surface act as if it had an elastic membrane,a property called surface tension. All liquids have surface tension, but water’s is higher because of the cohesion/hydrogen bonding between molecules.

Question 17

Why is water denser as a liquid than as a solid?

Answer 17

In ice, each water molecule can form four hydrogen bonds at one time. This forms a low-density crystal structure in ice, which is has a relatively large amount of space between molecules. However, hydrogen bonds in liquid water are constantly being made and broken. The liquid therefore does not form crystal lattices and they are much more closely packed together.

Question 18

What is specific heat?

Answer 18

Specific heat is the amount of energy required to raise the temperature of 1 gram of a substance by 1 degree Celsius.

Question 19

Why does water have a high specific heat?

Answer 19

The specific heat of water is high because or the amount of energy required to break the hyrdogen bond

Question 20

What is the heat of vaporization?

Answer 20

The heat of vaporization is the energy required to change 1 gram of a substance from a liquid to a gas.

Question 21

What do we know about water’s heat of vaporization?

Answer 21

The energy required is higher than that of most molecules that are liquid at room temperature, due to hydrogen bonding. As a result, water has to absorb a great deal of energy to evaporate.

Question 22

Why is water’s ability to absorb energy so critical to the theory of chemical evolution?

Answer 22

Compounds that were important in chemical evolution dissolve readily in water, they would have formed in the ocean or rained out of the atmosphere into the ocean. Once these compounds were in aqueous solution, they were well-protected from sources of energy that could break them apart. Thus, they continued to increase in concentration and react over time to continue the process of chemical evolution.

Question 23

What is disassociation?

Answer 23

it is a form of a chemical reaction within a water molecules in which H20 becomes a hydrogen ion (H+) and Hydroxide Ion (OH-). The hydrogen ion is simply a proton that associates with water molecules to form the hydronium ion (H30). This occues in in half a biliion

Question 24

What are acids?

Answer 24

Acids are substances that give up protons during chemical reactions and raise the hydrogen ion concentration of water.

Question 25

What are bases?

Answer 25

Bases are molecules or ions that acquire protons during chemical reactions and lower the hydrogen ion concentration of water

Question 26

Is water an acid or a base?

Answer 26

Water is both a weak acid and a weak base, but it (unlike most substances) can act as both an acid and a base.

Question 27

What is pH?

Answer 27

pH indicates the concentration of protons. By definition, the pH of a solution is the negative of the base-10 logarithm, or log, of the hydrogen ion concentration.
pH = -log [H+]

Question 28

What are buffers? Why are they important?

Answer 28

Buffers are compounds that minimize changes in pH, because they buffer a solution against the damaging effects of pH change. They are important to maintaining homeostasis (relatively constant conditions) in cells and tissues

Most buffers are weak acids (likely to give up a proton in a solution)

Question 29

How do chemical reactions happen?

Answer 29

Any process in which one compound or element is combined with others or is broken down; involves the making and/or breaking of chemical bonds.

Involves reactants and products

Question 30

What types of matter can be involved in a chemical reaction?

Answer 30

gases (g)
liquids (l)
solids (s)
and aqueous solutions (aq) - substances disolved in water

Question 31

What is chemical equilibrium?

Answer 31

A dynamic but stable state of a reversible chemical reaction in which the forwards and reverse reactions proceed at the same rate, so that the concentrations of reactants and products remain constant.

Can be altered by changes in temperature

Question 32

What is energy?

Answer 32

Energy is the capacity to do work or to supply heat. It exists as stored potential or as an active motion.

Question 33

What are the two major categories of energy?

Answer 33

Kinetic (constant motion) and potential energy (stored energy)

Question 34

What type of energies do molecules have?

Answer 34

Molecules have kinetic energy because they are constantly in motion. The kinetic energy of molecular motion is called thermal energy.

Question 35

What does temperature define?

Answer 35

The temperature of an object is a measure of how much thermal energy its molecules possess. If an object has a low temperature, its molecules are moving slowly. (“cold”) If an object has a high temp, its molecules are moving rapidly (“hot”)

Question 36

What is heat?

Answer 36

The transferred thermal energy between two objects with different temperatures.

Question 37

What is the first law of thermodynamics?

Answer 37

Energy cannot be created or destroyed, but only transferred or transformed

Question 38

What makes a chemical reaction spontaneous?

Answer 38

Chemical reactions are spontaneous if they proceed on their own, without any continuous external influence such as added energy.

Question 39

What two factors determine if a reaction is spontaneous or not?

Answer 39

1. if the products have lower potential energy than the reactants
2. if product molecules are less ordered than the reactant molecules.

Question 40

What is the second law of thermodynamics?

Answer 40

Physical and chemical processes proceed in the direction that results in lower potential energy and increased disorder.

Question 41

What is chemical energy?

Answer 41

the potential energy stored in chemical bonds

Question 42

What are organic molecules?

Answer 42

Molecules that contain carbon

Except for water, almost all molecules found in organisms contain carbon.

Question 43

Why is carbon important?

Answer 43

Carbon is the most versatile atom on Earth. It has four valence electrons, allowing it to form many covalent bonds, multiple combinations of double and triple bonds, and limitless molecular shapes.

Question 44

What is a functional group?

Answer 44

A functional group is a specific configuration of atoms commonly attached to the carbon skeleton of an organic molecule. Functional groups confer specific chemical properties to the molecules of which they are a part. Atoms typically found in functional groups include oxygen, nitrogen, sulfur, and phosphorus.

Question 45

What is the amino functional group?

Answer 45

−NH2 - It is of the amines family and acts as a base. It tends to attract a proton to form N+-H-H-H

Question 46

What is the carbonyl functional group?

Answer 46

This is in the aldehydes (COH) and ketones (>CO) family which react with certain compounds to from larger molecules

Question 47

What is the carboxyl functional group?

Answer 47

It belongs to the carboxylic acids family and acts as an acid, tending to lose a proton in a solution to form −COOH

Question 48

What is the hydroxyl functional group?

Answer 48

It is in the alcohols family (−OH). It is highly polar and makes compounds more soluble through hydrogen bonding with water. may also act as a weak acid and drop a proton

Question 49

What is a phosphate functional group?

Answer 49

−OP2 O3, belonging to organic phosphates

When several phosphate groups are linked together, breaking O-P bonds between them releases large amounts of energy.

Question 50

What is the sulfhydryl functional group?

Answer 50

−SH in the thiols family. When present in proteins it can form disulfide (S-S) bonds that contribute to protein structure