Sustainable Sustain- ability = the ability to sustain (last) One definition of sustainability is…To live in a way that meets the needs of today, without risking the ability of our children to meet their needs. To determine if an action is sustainable you can… consider the 3 Es: social equity, environmental, and economic impacts.
Hydrogen Bonding Water is ________________ and has an ___________________ oxygen atom which makes it very ______. The oxygen side of water has a partial ___________ charge and the hydrogen side of water has a partial __________ charge. This is called a ______ . Water is attracted to other water molecules by _________ _____ where the negative _________ side of one water is attracted to the positive __________ side of another water molecule. Because water is very _______ and can hydrogen bond with itself it has several unique properties! unsymmetrical electronegative polar negative positive dipole bonds hydrogen oxygen hydrogen polar
10 9 8 7 6 5 4 3 2 1 3/26 Hydrogen Bonding Draw as many “hydrogen bonds” as you can between oppositely charge poles of neighboring molecules.
Surface Tension surface tension One of water’s unique properties is its high _________________ . All liquids have surface tension that acts like a “_________” that is stretched tight across its surface. Water’s surface tension is especially high because water molecules are ______________ to each other by hydrogen bonding. When particles of the same substance are attracted to one another it is called ____________. skin attracted cohesion
Water on a Penny cohesion Surface Tension Attraction between particles of the SAME substance co = together, with co-worker co-operate co-exist
Capillary Action A second unique property of water is how well it undergoes __________ ________. Water is so polar it can also be attracted to other polar ____________ while “sticking” to itself. This can be seen in the familiar ____________ shape formed inside small glass tubes. This attraction between water and other substances is called _______________and allows water to travel up materials against gravity. In trees for example, water is absorbed by the roots and travels up the xylem (veins of the tree). Water can “climb” up materials because as the water molecules are attracted up the walls of a surface (___________) they simultaneously drag other water molecules along (_______________). capillary action surfaces meniscus adhesion adhesion cohesion
Formation of a Meniscus Adhesion and cohesion working together create a meniscus and cause CAPILLARY ACTION adhesion Attraction between particles of the DIFFERENT substances (in this case the plant and water molecules) Cohesion creates SURFACE TENSION ad = to In this case “to” stick to something else
Solubility Another unique property of water is that it is very good at dissolving many substances and therefore called the __________ _________. When an ionic solid like salt [NaCl] or polar liquid like methanol [CH3OH] is mixed into water it _____________. Once it dissolves the substance is called the __________ and the water is called the ____________. Therefore, we would say that compounds like salt and methanol are _____________ in water. Universal Solvent dissolves solute solvent soluble
Soluble vs. Insoluble Na+ Cl-
Why does salt dissolve in water? Why doesn’t oil dissolve in water?
Solubility oil soluble Non-polar compounds, like ______, are not water ___________ because hydrogen bonding between water is stronger than any attraction between the non-polar solute and the polar water solvent. Water is so polar that it can actually induce (force) oil molecules to have a temporary ___________, but this will not happen because water molecules would rather stick with other water molecules. The attraction of polar solvents to themselves prevents non-polar molecules from ever dissolving into polar solvents. This is summarized in the chemistry rule “_________________________________” . dipole Like Dissolves Like
10 9 8 7 6 5 4 3 2 1 3/28 Why Ice Floats Leave your Oil in Water CER’s out to be collected. Arrange 6 water molecules as shown This is the most common structure of ice! Imagine the crystal extending in all directions. 1. What shape does ice make? Notice the hole in the center. 2. Does the structure of ice take up more OR less space than the arrangement of molecules in a sample of liquid water?
Polarity of Water In liquid water, molecules are randomly and more densely arranged by changing hydrogen bonds As liquid water cools, the molecules slow down and hydrogen bonds arrange them into a hexagon shape
Hydrogen Bonding in Ice As liquid water cools, the molecules slow down and hydrogen bonds force a hexagon shape
Hydrogen Bonding in Water Another unique property of water is that it has a very high ______________________. This means that water can _______ and ________ large amounts of _______ as it is heated or cooled. However, these large changes in energy only result in _______ changes in _______________. In other words, water resists changes in temperature. This is because in before you can make the molecules move _______ the hydrogen bonds between them have to be ___________. Therefore, when you heat water most of the energy actually goes into breaking the hydrogen bonds. Water’s high specific heat helps to stabilize your body’s ______________ and the Earth’s different ____________ within a suitable range for life. specific heat capacity absorb release energy small temperature faster broken temperature climates
Specific Heat of Water Specific heat is defined as:the amount of energy needed to raise the temperature of 1 g of a substance by 1ºC. Water has a very high specific heat of 4.184
Specific Heat Equation q = m Cp ΔT x x Thermal energy Specific heat Change in temp. = x x Mass J Joules = °C Degrees Celsius g grams x x Joules per gram degree celsius Ratio of 3 variables
Specific Heat Lab Chemists conduct thermochemistry experiments in a device called a ______________ which prevents _____of thermal energy to the surroundings. For this experiment, you will heat a sample of metal in a beaker of boiling water. This will allow you to assume that the metal and water are in __________ _____________, meaning the metal is the _______ temperature as the boiling water (_______). Then, you will place the hot metal into a calorimeter containing room temperature water. By putting the hot metal into the room temperature water, the metal will _______ and the water will heat up until the two reach thermal equilibrium (the same ___________________). calorimeter loss equilibrium thermal same 100°C cool temperature
Summary Water’s polarity and Hydrogen bonding explains these five unique properties ! High Specific Heat Surface Tension Capillary Action Universal Solvent Density of Ice