Properties of Water
Key Concepts and Vocabulary What is the structure of a water molecule? What are the important properties of water? Why is water essential for life? Vocabulary: Polarity Hydrogen bond Adhesion Cohesion Specific heat Solute Solvent Acid Base
Structure of a Water Molecule A water molecule contains two hydrogen atoms bonded to one oxygen atom Draw a water molecule in the space below: It looks like Mickey Mouse!
Polarity Polarity – molecule that has two “poles,”– a positive and negative end. In water, the oxygen atom has a negative charge, and the hydrogen atoms are positively charged. Therefore water is a polar molecule
Bonding Hydrogen bonds – the positive hydrogen of one water molecule is attracted to the negative oxygen of another water molecule. Hydrogen bonds give water unique properties Draw a diagram of the hydrogen bonds of water in the space below:
Properties of Water Cohesion - Water molecules stick to each other Creates surface tension on water’s surface What are some other examples of surface tension?
Properties of Water Adhesion - Water molecules stick to other substances Causes capillary action - the ability of water to climb tubes In what organisms might capillary action be important?
Properties of Water High Specific Heat - Large amounts of heat are needed to raise water’s temperature Why?
Properties of Water High heat capacity - Water absorbs heat as it evaporates Helps to cool off organisms
Properties of Water Density – solid water is less dense than liquid water. Allows ice to float, preventing large bodies of water from freezing solid
Properties of Water Universal Solvent - water can dissolve most substances
Solution Chemistry Solutions – a uniform mixture of two substances Solute – the substance that is being dissolved Solvent – the substance the solute dissolves into.
Acids and Bases Acid – a solution that releases H+ ions in a solution Base – a solution that releases OH- ions in a solution pH – the scale used to measure how acidic or basic something is.
Why is Water Important? How much of the human body is water? The planet earth? Why is water so important for living organisms?