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.