Lesson 1.2 - Water: Life's Solvent Flashcards
How does the structure of water account for its properties, such as its boiling point, surface tension, and adhesion?
Water’s lattice structure is stable which leads to a high specific heat of water. High specific heat gives water a high boiling point. The lattice structure keeps molecules close causing high surface tension. Water has the ability to form H-bonds with other polar molecules, which gives water its adhesion properties.
Is the following a trait of acids or bases?
Ability to turn blue litmus paper red.
Acids
Water molecules are _____ and strongly _____, therefore water dissolves other _____ molecules and ions.
Water molecules are small and strongly polar, therefore water dissolves other polar molecules and ions.
Much of the thermal energy that flows into water is used by the process of breaking _____, therefore the temperature rises relatively slowly.
Much of the thermal energy that flows into water is used by the process of breaking H-bonds, therefore the temperature rises relatively slowly.
As polar molecules or charged ions dissolve in solution, they are completely surrounded by water molecules, which reduce the _____ interactions between them.
As polar molecules or charged ions dissolve in solution, they are completely surrounded by water molecules, which reduce the electrostatic interactions between them.
Is the following a trait of acids or bases?
Sour Taste
Acids
Water has a high _____ (the amount of thermal energy that is required to increase the temperature of a given quantity of a substance by 1 °C) due to the stabilizing hydrogen bond lattice.
Water has a high specific heat (the amount of thermal energy that is required to increase the temperature of a given quantity of a substance by 1 °C) due to the stabilizing hydrogen bond lattice.
Pure H2O is a mixture of H2O molecules, OH- (hydroxide) ions and H3O+ (hydronium) ions. At 25 °C, about 2 in 550 million H2O molecules react and form OH- and H3O+ ion. [This is] called _____.
Pure H2O is a mixture of H2O molecules, OH- (hydroxide) ions and H3O+ (hydronium) ions. At 25 °C, about 2 in 550 million H2O molecules react and form OH- and H3O+ ion. [This is] called autoionization.
What is a chemical that compensates for pH changes in a solution be accepting or donating H+ ions known as?
Buffer
A _____ is a weak acid or base that can compensate for changes in a solution to maintain the proper pH level.
A buffer is a weak acid or base that can compensate for changes in a solution to maintain the proper pH level.
[A buffer is] a substance that minimizes changes in pH by _____ or _____ hydrogen ions as needed.
[A buffer is] a substance that minimizes changes in pH by donating or accecpting hydrogen ions as needed.
Ability to turn red litmus paper blue.
Bases
The proper _____ of cells inside living organisms and their environment is critical for the survival of the organisms.
The proper pH of cells inside living organisms and their environment is critical for the survival of the organisms.
Will water form a surface coat around a molecule, such as octane, CH3(CH2)6CH3? Explain.
No, because octane is non-polar and no bonding will occur.
How does polarity influence water’s role as a solvent?
Polar water molecules can surround polar biological molecules or ions, thus dissolving them.
Is the following a trait of acids or bases?
[OH-] > [H3O+] in solution
Bases
Water is strongly _____ (the proeprty of like molecules sticking together) as each molecule may make 4 _____.
Water is strongly cohesive (the proeprty of like molecules sticking together) as each molecule may make 4 H-bonds.
Why is it important that we help to maintain the proper pH of our environment?
Changes in pH of the environment can have a negative impact on organisms by inhibiting or altering chemical reactions critical to normal metabolism and the health.
_____ (measure of how difficult it is to stretch/break the surface of a liquid) is related to cohesion.
Surface tension (measure of how difficult it is to stretch/break the surface of a liquid) is related to cohesion.
Why would it be inaccurate to say that a buffer is a solution that maintains a constant pH?
A buffer solution is one that maintains a relatively constant pH when H+ or OH- are added. However, the pH can change slightly. It remains relatively constant not completely constant.
What determines whether an acid or a base is classified as strong or weak? Explain your answer.
The degree of ionization or dissociation determines its classification. Strong acids or bases completely dissociate or ionize while a weak acid or base does not.
How do acids and bases differ in terms of how they behave when added to pure water?
Acids when placed in aqueous solution cause the production of hydronium ions, increasing H+ concentration and lowering the pH. Bases cause the production of hydroxide ions in aqueous solution, increasing OH- concentration, and raising the pH.
Is the following a trait of acids or bases?
Ability To Conduct Electricity
Ha, it’s both! I hope I messed you up and you’re really pissed at me right now but since I made all these flashcards for you to use for free you can just shut up and move along.
What is the amount of thermal energy required to raise the temperature of a given quantity of a substance by 1 ºC known as?
Specific Heat
Define Autoionization
The process in which a molecule spontaneously dissociates into ions.
What are non-polar molecules that are not strongly attracted to water known as?
Hydrophobic
What is the process in which a molecule spontaneously dissociates into ions known as?
Autoionization
There are hydrogen bonds between molecules (a type of _____ force).
There are hydrogen bonds between molecules (a type of intermolecular force).
Is the following a trait of acids or bases?
Bitter Taste (Slippery Feel)
Bases
A lot of _____ energy and a relatively high _____ (100 °C) are needed to break enough bonds in H2O for it to boil.
A lot of thermal energy and a relatively high temperature (100 °C) are needed to break enough bonds in H2O for it to boil.
In our blood, a buffering system that is based on _____ acid (a week acid) helps to maintain proper blood pH levels. [Since] it is a weak acid, the reaction is _____ (unlike reactions with strong acids).
In our blood, a buffering system that is based on carbonic acid (a week acid) helps to maintain proper blood pH levels. [Since] it is a weak acid, the reaction is reversible (unlike reactions with strong acids).
Potassium bromide, KBr, is an ionic compound. Describe what happens to its ions when it is dissolved in water.
When potassium bromide, KBr, is dissolved in water it dissociates into potassium ions, K+ , and bromine ions, Br- ions. These ions are enveloped by water molecules to form a surface coat.
Define Hydrophobic
Non-polar molecules that are not strongly attracted to water.
Water forms a _____ structure through hydrogen bonding in liquid water and ice.
Water forms a lattice structure through hydrogen bonding in liquid water and ice.
[Since] “like dissolves like”, _____ substances such as sugars are highly soluble in water.
[Since] “like dissolves like”, polar substances such as sugars are highly soluble in water.
_____ acids and bases dissociate completely in water. _____ acids and bases dissociate only partially in water. Acids and bases react to form water and a salt in _____ reactions.
Strong acids and bases dissociate completely in water. Weak acids and bases dissociate only partially in water. Acids and bases react to form water and a salt in neutralization reactions.
Define Specific Heat
The amount of thermal energy required to raise the temperature of a given quantity of a substance by 1 ºC.
Define Hydrophilic
Polar or charged molecules that are strongly attracted to water.
What are polar or charged molecules that are strongly attracted to water known as?
Hydrophilic
[In liquid water,] ______ constantly break and reform giving water its fluid properties.
[In liquid water,] H-bonds constantly break and reform giving water its fluid properties.
[When sodium chloride is put in water, the] water molecules quickly form _____ around the Na+ and the Cl- ions of the salt crystal, reducing the attraction so much that they seperate from their normal crystal lattice structure and enter the surrounding H2O as _____.
[When sodium chloride is put in water, the] water molecules quickly form hydration shells around the Na+ and the Cl- ions of the salt crystal, reducing the attraction so much that they seperate from their normal crystal lattice structure and enter the surrounding H2O as hydrated ions.
What’s denser, liquid water or solid water (ice)?
Liquid Water
How do buffers in your cells help to keep your body functioning properly?
Buffers help to maintain proper pH levels in different cells in the body by being able to absorb excess hydronium or hydroxide ions. Buffers use systems of weak acids or weak bases to accomplish this.
Water molecules on the surface of a body of water can form _____ on all sides, except the side that faces the air, which causes them to be under tension making them more resistant to _____.
Water molecules on the surface of a body of water can form H-bonds on all sides, except the side that faces the air, which causes them to be under tension making them more resistant to seperation.
[In solid water (ice),] 1 H2O molecule will form _____ H-bonds with other H2O molecules.
[In solid water (ice),] 1 H2O molecule will form 4 H-bonds with other H2O molecules.
The hydrogen bonding of water molecules to one another gives water a high _____.
The hydrogen bonding of water molecules to one another gives water a high surface tension.
Is the following a trait of acids or bases?
[H3O+] > [OH-] in solution
Acids
Water molecules form H-bond with other _____ molecules.
Water molecules form H-bond with other polar molecules.
Water is a polar molecule. Explain how the polarity of water accounts for its lattice structure.
The polarity of water helps the formation of hydrogen bonds among water molecules. Hydrogen bonds create the lattice structure of water.
Polar molecules or charged ions that are strongly attracted to H2O are called _____.
Polar molecules or charged ions that are strongly attracted to H2O are called hydrophilic.
Define Buffer
A chemical that compensates for pH changes in a solution be accepting or donating H+ ions.
[In liquid water,] 1 H2O molecule will from, on average, _____ H-bonds with other H2O molecules.
[In liquid water,] 1 H2O molecule will from, on average, 3.4 H-bonds with other H2O molecules.
Non-polar molecules that are not strongly attracted to water are called _____.
Non-polar molecules that are not strongly attracted to water are called hydrophobic.
