Importance of Water

Importance of Water​

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​Universal Solvent

​Water’s extensive capability to dissolve a variety of molecules has earned it the designation of “universal solvent,” and it is this ability that makes water such an invaluable life-sustaining force.  On a biological level, water’s role as a solvent helps cells transport and use substances like oxygen or nutrients. Water-based solutions like blood help carry molecules to the necessary locations. Thus, water’s role as a solvent facilitates the transport of molecules like oxygen for respiration

​Unique Properties of Water

• ​Universal Solvent

• ​Cohesion

• ​Adhesion

• ​Surface Tension

• ​Capillary Action

• ​Density

• ​High Specific Heat

Multiple Choice

Water is a polar molecule, which means it has a positive and a negative side. Hydrogen bonds form when:

• _{The positive end of one water molecule bonds to the positive end of another water molecule.}

• _{The negative end of one water molecule bonds to the negative end of another water molecule.}

• _{The positive end of one water molecule bonds to the negative end of another water molecule.}

Multiple Choice

The ability of water molecules to stick to each other, creating surface tension is called:

• Cohesion

• Adhesion

• Insulation

• Ph

Multiple Choice

The fact that water can stick to other substances is called:

• Ph

• Adhesion

• Cohesion

• Insulation

Multiple Choice

What property of water allows it to be such a versatile solvent that it is often called the "universal solvent?"

• Purity
• Polarity

• High heat capacity
• Expansion upon freezing

Multiple Choice

Large bodies of water do not quickly fluctuate in temperature. Why?

• Water is a solvent.
• Water has a high heat capacity.
• Water acts as a buffer.
• Water is non-polar.

Multiple Choice

What two elements make up water?

• Helium and oxygen
• Hydrogen and oxygen
• helium and carbon
• oxygen and carbon

Multiple Choice

Why does water move from the roots to the leaves of plants?

• Water is pushed by solutes
• Capillary action pulls the water molecules like a chain
• Water is pulled by gravity
• Water’s cohesion causes it to “pull” towards the leaves

Multiple Choice

Why does ice float?

• As water freezes, it expands and its density decreases.
• As water freezes, it takes up more hydrogen from the atmosphere, causing it to have a greater buoyancy.
• As water freezes, air becomes trapped between the hydrogen bonds of water molecules.
• As water freezes, it takes up more oxygen from the atmosphere, causing it to have a greater buoyancy.

Multiple Choice

Water is polar because...

• The unequal sharing of electrons gives the water molecule a slight negative charge near its oxygen atom and a slight positive charge near its hydrogen atoms.
• The molecule has two poles, at which the it is colder than other regions of the molecule.
• The unequal sharing of electrons gives the water molecule a slight negative charge near its hydrogen atoms and a slight positive charge near its oxygen atom.
• The water molecule is neutral.

Multiple Choice

Which types of compounds dissolve easily in water?

• Polar and Nonpolar
• Polar and Ionic
• Nonpolar and Ionic
• Covalent and Nonpolar

​Chemical Reactions & Water

​Water is directly involved in many chemical reactions to build and break down important components of the cell. Photosynthesis, the process in plants that creates sugars for all life forms, requires water. Water also participates in building larger molecules in cells. Molecules like DNA and proteins are made of repetitive units of smaller molecules. Putting these small molecules together occurs through a reaction that produces water. Conversely, water is required for the reverse reaction that breaks down these molecules, allowing cells to obtain nutrients or repurpose pieces of big molecules. 

​Acids & Bases

Additionally, water buffers cells from the dangerous effects of acids and bases. Highly acidic or basic substances, like bleach or hydrochloric acid, are corrosive to even the most durable materials. This is because acids and bases release excess hydrogens or take up excess hydrogens, respectively, from the surrounding materials.  Losing or gaining positively-charged hydrogens disrupts the structure of molecules.​