3. Water

Properties of Water- The Universal Solvent

Why Water Is Called Universal Solvent? | #facts | #education | #science | #knowledge

Hydrophilic vs Hydrophobic | Substances | Cell Membranes

Are nonpolar water “fearing” molecules.

Are nonpolar water “loving” molecules.

Hydrophobic molecules:a) Are polar covalent molecules.b) Easily dissolve in water.c) Are nonpolar water “fearing” molecules.&nbsp;d) Are nonpolar water “loving” molecules.

Water as a solvent | Water, acids, and bases | Biology | Khan Academy

What is the charge of the solute molecule in the image below based on the polarity of water?<img src="https://static.studychannel.pearsonprd.tech/courses/biology/thumbnails/2f428769" class="fr-fic fr-dii">a) Positively charged.b) Negatively charged.c) Uncharged.d) Non-polar and hydrophobic.

 stir 342 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution to 1 L 

No. This would produce a 1-molar (1 M) solution.

 stir 684 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 2 L 

 stir 684 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 0.5 L 

No. This would produce a 4-molar (4 M) solution.

 stir 342 g of sucrose in water to dissolve the sugar, and then add enough water to bring the total volume of the solution up to 0.5 L 

What is the relationship between moles and daltons?

Sucrose has a molecular mass of 342 daltons. To make a 2-molar (2 M) solution of sucrose, __________.

The substance in a mixture that is dissolved is called the:a) Solution.b) Solvent.c) Solute.d) Aqueous solution.

 No. Water does dissociate to form ions, but this does not make water a versatile solvent. 

 No. Hydrophobic molecules have a prevalence of nonpolar covalent bonds, whereas water is a highly polar molecule. 

What is the underlying cause of water's emergent properties?

Water is a very versatile solvent because water molecules are __________.

 Water's polarity allows it to form covalent bonds with many substances. 

 No. Covalent bonding is not involved in solubility. 

 Natural water has a pH of approximately 5.6, which is slightly acidic. Acids can dissolve more substances than bases can. 

 No. The pH affects the types of substances that water can effectively dissolve, but it does not explain the role of water's polarity. 

 Because it is polar, water forms ionic bonds with the ions in substances such as NaCl (salt). 

 No. Water's polarity leads to the formation of hydrogen bonds, not ionic bonds. 

 Because it is polar, water's negatively charged oxygen atoms and positively charged hydrogen atoms are attracted to positively and negatively charged ions and molecules. 

What happens when substances dissolve in water?

How does the polarity of water contribute to its ability to dissolve so many substances?

DRAW IT Draw the hydration shells that form around a potassium ion and a chloride ion when potassium chloride (KCl) dissolves in water. Label the positive, negative, and partial charges on the atoms.

Importance of water for life | Chemistry of life | AP Biology | Khan Academy

Properties of Water

Most of the unique properties of water result from the fact that water molecules
a. are the most abundant molecules on Earth’s surface.
b. are held together by covalent bonds.
c. are constantly in motion.
d. are polar and form hydrogen bonds.

No. This would produce a 2 M or a 2,000 mM solution. Remember that milli- means “thousandth.”

No. This would produce a 0.2 M or a 200 mM solution.

No. This would produce a 0.02 M or a 20 mM solution.

A mole of any substance is a mass in grams with the same numerical value as the molecular mass.

A mole of ethyl alcohol weighs 46 g. How many grams of ethyl alcohol are needed to produce 1 L of a 2-millimolar (2 mM) solution?

Hydrophilic vs. Hydrophobic

Create a concept map to organize your understanding of the life-supporting properties of water. A sample map is in the answer section, but the value of this exercise is in the thinking and integrating you must do to create your own map.

What do you think the effect on the properties of water would be if oxygen and hydrogen had equal electronegativity?

Which of the following is a hydrophobic material?
a. paper
b. table salt
c. wax
d. sugar

The components of a heterogenous solution are ________________ distributed throughout.a) Equally.&nbsp;b) Unequally.c) Uniformly.

Homogenous vs. Heterogenous Solutions

A solution in which water is the solvent is called a(n) _______________ solution.a) Polar.b) Aqueous.c) Hydrophobic.d) &nbsp;Complete.

No. The suffix -philic means “loving.”

 None of the listed responses is correct. 

Consider the meanings of the prefixes and suffixes.

What are nonpolar molecules that cluster away from water molecules called?

 No. Hydrophilic substances have an affinity for water.  A molecule with all nonpolar bonds would not have an affinity for water and therefore would not be hydrophilic. 

No. Acidic refers to the hydrogen ion concentration of a solution, not to the affinity or lack of affinity a substance has for water.

No. Basic refers to the hydrogen ion concentration of a solution, not to the affinity or lack of affinity a substance has for water.

Contrast this with the nature of the bonds present in a water molecule.

A molecule that has all nonpolar covalent bonds would be __________.

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1. Introduction to Biology

2. Chemistry

4. Biomolecules

5. Cell Components

6. The Membrane

7. Energy and Metabolism

8. Respiration

9. Photosynthesis

10. Cell Signaling

11. Cell Division

12. Meiosis

13. Mendelian Genetics

14. DNA Synthesis

15. Gene Expression

16. Regulation of Expression

17. Viruses

18. Biotechnology

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30. Overview of Animals