Lesson 3: Properties of Water Flashcards
What type of bond is present in water?
Covalent bond
Water is covalently bonded, but is polar.
Why is water considered polar?
The shared electrons spend more time with oxygen than hydrogen, creating a slight negative charge on oxygen and a slight positive charge on hydrogen.
What are hydrogen bonds?
Attractions between partially positive hydrogen and partially negative atoms like oxygen and nitrogen
Hydrogen bonds are represented by dotted lines because they are weak and easily broken.
How do hydrogen bonds contribute to the properties of water?
Numerous hydrogen bonds can add up to have large effects, explaining unique properties of water.
What percentage of the human body is water?
Approximately 70% water.
What substances can enter/cross the cell membrane?
Only substances dissolved in water, such as glucose and amino acids.
What role does water play in waste removal from cells?
Water carries away dissolved wastes from cells and wastes excreted in liquid forms like sweat and urine.
Which ions are necessary for many body processes?
Ions such as Ca+, Na+, and K+
These are important for movement and generation of nerve impulses.
What is the significance of water in maintaining body temperature?
Water absorbs much heat before warming up or boiling, and gives off heat before freezing.
What are the critical survival timeframes without essential elements?
Three minutes without breathing, three hours in extreme temperatures, three days without water, three weeks without food.
Why does water have a low freezing point and a high boiling point?
Due to hydrogen bonding, water remains liquid at body temperature.
What is the density relationship between liquid water and ice?
Liquid water is more dense than ice, causing ice to float on top.
What is the universal solvent?
Water
Water dissolves many substances, especially polar molecules, promoting chemical reactions.
What property of water allows it to transport materials through tubes?
Cohesiveness
Water molecules tend to cling together, drawing dissolved substances along.
What is surface tension?
The cohesion of water molecules at the surface of a body of water.
What causes water to expand when it freezes?
The configuration of hydrogen bonds in water.
What are the main properties of water?
Universal solvent, cohesion and adhesion, high surface tension, high heat capacity, changes in density.
