Structure Of Water And Hydrogen Bonding

Question 1

What is water made from

Answer 1

2 hydrogen and 1 oxygen

Question 2

What is more electronegative in water?

Answer 2

Oxygen

Question 3

What kind of bonds does water have?

Answer 3

Polar covalent between hydrogen and oxygen. Hydrogen bond between water molecules.

Question 4

What is a polar covalent bond?

Answer 4

A chemical bond where a pair of electrons are unequally shared.

Question 5

How much of the human body is made from water?

Answer 5

60-70%

Question 6

What is key to the existence of life?

Answer 6

Water

Question 7

What is the base of cytosol in a cell?

Answer 7

Cytosol is water based.

Question 8

What are some of the properties of water?

Answer 8

Solvent
Cohesion and adhesion
High specific heat and vaporization
Low density when frozen
Polarity

Question 9

What creates surface tension in water?

Answer 9

Hydrogen bonding. Cohesion of water molecules.

Question 10

What are intermolecular forces?

Answer 10

Forces of attraction or repulsion between neighboring particles (atoms, molecules, or ions).

Question 11

True or False: Intermolecular forces are generally weaker than intramolecular forces.

Answer 11

True

Question 12

Name the four main types of intermolecular forces.

Answer 12

Dispersion forces, dipole-dipole forces, hydrogen bonds, and ion-dipole forces.

Question 13

Fill in the blank: London dispersion forces are also known as __________ forces.

Answer 13

van der Waals

Question 14

Which type of intermolecular force is the strongest?

Answer 14

Hydrogen bonds

Question 15

What is the primary cause of dipole-dipole interactions?

Answer 15

The presence of permanent dipoles in polar molecules.

Question 16

True or False: Hydrogen bonds can only occur between hydrogen and oxygen.

Answer 16

False

Question 17

What type of molecules exhibit London dispersion forces?

Answer 17

All molecules, regardless of polarity.

Question 18

Multiple Choice: Which of the following molecules would likely exhibit the strongest hydrogen bonding? A) H2O B) CH4 C) NH3 D) HF

Answer 18

A) H2O

Question 19

What factors affect the strength of London dispersion forces?

Answer 19

Molecular size and shape.

Question 20

Fill in the blank: Ion-dipole forces are particularly important in __________.

Answer 20

solutions of ionic compounds

Question 21

True or False: The boiling point of a substance is influenced by the strength of its intermolecular forces.

Answer 21

True

Question 22

What is the relationship between intermolecular forces and volatility?

Answer 22

Stronger intermolecular forces lead to lower volatility.

Question 23

Define hydrogen bond.

Answer 23

A strong dipole-dipole interaction between a hydrogen atom bonded to a highly electronegative atom and another electronegative atom.

Question 24

Multiple Choice: Which of the following is NOT a characteristic of dipole-dipole interactions? A) Occur in polar molecules B) Weaker than hydrogen bonds C) Stronger than London dispersion forces D) Occur in nonpolar molecules

Answer 24

D) Occur in nonpolar molecules

Question 25

What type of intermolecular force is present in nonpolar molecules?

Answer 25

London dispersion forces

Question 26

True or False: Larger atoms generally have stronger London dispersion forces.

Answer 26

True

Question 27

What is the effect of temperature on intermolecular forces?

Answer 27

Increasing temperature generally weakens intermolecular forces.

Question 28

Name a property of water that is largely due to hydrogen bonding.

Answer 28

High surface tension

Question 29

What determines the polarity of a molecule?

Answer 29

The difference in electronegativity between the atoms and the molecular geometry.

Question 30

Multiple Choice: Which compound would have the highest boiling point? A) CH4 B) H2O C) C2H6 D) CO2

Answer 30

B) H2O

Question 31

Fill in the blank: The strength of intermolecular forces is generally __________ related to the size of the molecule.

Answer 31

directly

Question 32

What are dipole-induced dipole forces?

Answer 32

Forces that occur when a polar molecule induces a dipole in a nonpolar molecule.

Question 33

True or False: All intermolecular forces are attractive.

Answer 33

False

Question 34

What is the role of intermolecular forces in solubility?

Answer 34

Intermolecular forces determine whether substances can mix or dissolve in each other.

Question 35

What is surface tension?

Answer 35

Surface tension is the property of a liquid's surface that allows it to resist an external force, due to the cohesive nature of its molecules.

Question 36

True or False: Surface tension is only present in liquids.

Answer 36

True

Question 37

What unit is surface tension commonly measured in?

Answer 37

Surface tension is commonly measured in dynes per centimeter (dyn/cm) or newtons per meter (N/m).

Question 38

Fill in the blank: The molecules at the surface of a liquid experience _____ forces compared to those in the bulk of the liquid.

Answer 38

unequal

Question 39

Which of the following liquids generally has the highest surface tension? (a) Water (b) Mercury (c) Oil

Answer 39

b) Mercury

Question 40

What phenomenon allows small insects to walk on water?

Answer 40

Surface tension

Question 41

True or False: Increasing temperature generally decreases surface tension.

Answer 41

True

Question 42

What is the effect of surfactants on surface tension?

Answer 42

Surfactants lower surface tension.

Question 43

What is the term for the curved surface of a liquid in a container?

Answer 43

Meniscus

Question 44

Short answer: Name one application of surface tension in everyday life.

Answer 44

Soap bubbles or the ability of water to form droplets.

Question 45

Fill in the blank: Surface tension is caused by the _____ forces between liquid molecules.

Answer 45

cohesive

Question 46

What is the relationship between surface area and surface tension?

Answer 46

Surface tension acts to minimize the surface area of a liquid.

Question 47

True or False: Surface tension can be observed in gases.

Answer 47

False

Question 48

What is the significance of the Young-Laplace equation in relation to surface tension?

Answer 48

It describes the pressure difference across the interface of a curved liquid surface due to surface tension.

Question 49

What does the term 'capillarity' refer to?

Answer 49

Capillarity refers to the ability of a liquid to flow in narrow spaces without the assistance of external forces, influenced by surface tension.

Question 50

Short answer: How does surface tension affect the shape of liquid droplets?

Answer 50

Surface tension causes liquid droplets to form a spherical shape.

Question 51

What is the critical surface tension?

Answer 51

The critical surface tension is the minimum surface tension at which a liquid can wet a solid surface.

Question 52

True or False: Surface tension is a result of adhesive forces between different substances.

Answer 52

False

Question 53

What role does surface tension play in the formation of bubbles?

Answer 53

Surface tension creates a skin around the bubble, maintaining its shape and structure.

Question 54

Fill in the blank: The balance of cohesive and adhesive forces determines the _____ of a liquid.

Answer 54

wetting behavior

Question 55

What is the relationship between molecular size and surface tension?

Answer 55

Generally, larger molecules can lead to higher surface tension due to increased cohesive forces.

Question 56

Short answer: Describe one method to measure surface tension.

Answer 56

One method is the drop weight method, where the weight of a droplet is measured before it detaches.

Question 57

What is the effect of impurities on surface tension?

Answer 57

Impurities can either increase or decrease surface tension depending on their nature.

Question 58

True or False: Surface tension is a static property and does not change over time.

Answer 58

False

Question 59

What is a common example of a surfactant?

Answer 59

Soap

Question 60

Fill in the blank: Surface tension is crucial for the phenomenon of _____ in plants.

Answer 60

transpiration

Question 61

_________ forces are responsible for surface tension.

Answer 61

Cohesion/cohesive

Question 62

True or False Hydroxyl groups are polar

Answer 62

True

Question 63

What are two things hydroxyl groups can do?

Answer 63

-turn molecules into alcohols -allow molecules to dissolve in water

Question 64

What can carboxyl groups do?

Answer 64

Carboxyl groups can donate hydrogen ions, so they make molecules acidic.

Question 65

What do amino functional groups do?

Answer 65

Amino groups can pick up hydrogen ions from the surroundings, so they make molecules basic.

Question 66

What are 7 functional groups commonly attached to hydrocarbons?

Answer 66

-hydroxyl -carboxyl -amino -sulfhydryl -carbonyl -methyl -phosphate