Water and Aqueous Systems

Slides:



Advertisements
Similar presentations
Chapter 15 Water.
Advertisements

Aqueous Solutions Section 17.3.
Aqueous Solutions Sections 17.3 and 4.
Water and Aqueous Systems
Section 17.3 Homogeneous Aqueous Solutions
Chapter 15 Water and Aqueous Systems 15.2 Homogeneous Aqueous Systems
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Chapter 15 Water and Aqueous Systems 15.1 Water and Its Properties 15.2 Homogeneous.
Water, Water Everywhere, But Where’s the Solution?
WATER AND AQUEOUS SOLUTIONS
Solutions Solution Solute Solvent
POLAR BONDS AND MOLECULES NOTES Covalent Bonds  bond in which two atoms share a pair of electrons. 1. Single bond = 1 shared pair of electron 2.
Chapter 17 Section 3 aqueous solution- water sample containing dissolved substances solvent- dissolving medium, what does the dissolving *water is known.
CHAPTER 17 and 18 WATER AND AQUEOUS SOLUTIONS.  Water 1. Structure of water (H 2 O) a. two atoms of hydrogen b. One atom of oxygen c. Bent structure.
Chapter 15.  Water covers about three quarters of Earth’s surface. All life forms that are known to exist are made mostly of water. You will learn about.
Homogeneous Aqueous Systems Dr. Yager Prentice-Hall Chapter 15.2.
Chapter 15 Review “Water and Aqueous Systems” Pre-AP Chemistry Charles Page High School Stephen L. Cotton.
Water and Aqueous Systems
“Water and Aqueous Systems” “Aqua” Latin = water.
Aqueous Solutions Solution: Homogeneous mixture; solid liquid, or gas Soluble: Capable of being dissolved Solute: Substance that is dissolved, present.
Solutions The inward pull that tends to minimize the surface is called surface tension. Surface tension acts like a thin skin. A liquid that has strong.
NOTES: Chapter 15 – Water and Aqueous Systems. Chapter Objectives: Describe hydrogen bonding in water and how it explains water’s unique properties and.
Chapter 15 “Water and Aqueous Systems”
Chapter 12 Water.
Aqueous Solutions Solution - a homogenous mixture mixed molecule by molecule. Solution - a homogenous mixture mixed molecule by molecule. Solvent - the.
Water and Aqueous Systems
Unit 11- Solubility Water & Solutions. I. Water A. The Molecule 1. O—H bond is highly polar 2. Bond angle 105° making it Bent shaped 3. Water Molecule.
Chapter 15: Water and Aqueous Systems
Chapter 17 “Water and Aqueous Systems”
Chapter 17 Water and Aqueous Systems
Ch. 15: Water and Aqueous Systems
Matter Solution PreAP. Define Solution 1. A solution is a uniform, homogeneous mixture of two or more substances. 2. It consist of two parts: – a. solute.
Water and Aqueous Solutions. Intermolecular Forces These are the attractions between molecules not within the molecule These forces dictate what state.
What Are Solutions? Solution: homogeneous mixture of 2 or more substances Solution: homogeneous mixture of 2 or more substances –Solid, liquid, or gas.
Water and aqueous systems. Water is unique  High polarity Forms extensive hydrogen bonds with other molecules Forms extensive hydrogen bonds with other.
 Liquid Water and Its Properties  Water Vapor and Ice  Aqueous Systems  Heterogeneous Aqueous Systems.
Chapter 17: Water and Aqueous Systems
Chapter 15 “Water and Aqueous Systems” Pre-AP Chemistry Charles Page High School Stephen L. Cotton.
Solutions Aqueous Solutions. Review How do ionic and molecular compounds differ? The molecules in molecular compounds are electrically neutral, covalently.
Chapter 15 – Water and Aqueous Systems Water has some unusual properties. It has a high boiling point for a compound that has a small molar mass. The solid.
 Triatomic molecule  Contains covalent bonds  Includes partial positive and partial negative charges  Where do these charges come from?
1. Properties of Water Polar molecule Forms hydrogen bonds High Cohesion and surface tension Density – greatest at 4 o C Universal solvent Forms hydrates.
Water and Aqueous Systems Chapter 17. Objectives 1.Describe the hydrogen bonding that occurs in water 2.Explain the high surface tension and low vapor.
Water. Ice Liquid water’s density is greatest 4 o C. Ice has a 10% greater volume; therefore, lower density.
Water and Aqueous Systems
Chapter 13 Water and Its Solutions Section 13.2 Solutions and Their Properties.
Chapter 15 water and aqueous systems
Part I: Basic properties of pure water.. Water Molecule Triatomic (3 atoms) Bent Shape (104.45°) Polar Molecule δ+δ+ δ+δ+ δ-δ-
IPC Notes Water. Water is a polar molecule because it has a separation of charge. It also undergoes Hydrogen bonding, which is an attraction between the.
SOLUTIONS A homogeneous mixture in which the components are uniformly intermingled.
Homogeneous and Heterogeneous Aqueous Systems. Key Questions What is the difference between a solute and a solvent? What happens in the solution process?
Foothill Chemistry. Water Water covers ¾ of the Earth’s surface Water is essential to all life on Earth. Water is a polar molecule Water molecules are.
Chapter 13 Section 4 Solutions: Physical Properties of Solutions Ridgewood High School
WATER AND AQUEOUS SOLUTIONS Part I. I. Properties of Liquids A. Water 11. Water is a triatomic molecule with covalent H-O bonds. 22. Water experiences.
Chapter 17 “Water and Aqueous Systems” Mrs. Hudson Chemistry.
Objective: To have a basic understanding of solutions Do Now: What condition(s) do you think will dissolve sugar the quickest? a.Increase of temperature.
Water and Aqueous Systems Quick Review. Properties of Water Hydrogen bonding – Result in high surface tension and low vapor pressure – **What is a surfactant?
Chapter 15 “Water and Aqueous Systems”. The Water Molecule l Each O-H bond is highly polar, –high electronegativity of the oxygen l Water is bent, /\,
Chapter 15 Water and Aqueous Systems 15.2 Homogeneous Aqueous Systems
Chapter 15 Review “Water and Aqueous Systems”
Chapter 15 Review “Water and Aqueous Systems”
Water and Aqueous Systems
Chapter 15 “Water and Aqueous Systems”
Homogeneous Aqueous Systems
An aqueous solution is water that contains dissolved substances.
Unit 8 – Solutions – Properties of Water as Universal Solvent
Unit 8 – Solutions – Properties of Water as Universal Solvent
Bellwork Tuesday Today we are learning about solutions.
Water and it’s properties
Water.
Presentation transcript:

Water and Aqueous Systems Ch. 17

Liquid Water and its Properties 17-1

The Water Molecule, in review… The water molecule, H – O – H, is made up of covalent bonds that are highly polar. It has a bent shape with 105° bond angles. Oxygen has a slightly negative charge (more electronegative), while Hydrogen has a slightly positive charge. Water molecules attracted to each other through hydrogen bonds.

DRAW!

Many unique and important properties of water are due to it’s hydrogen bonds! Including its… High surface tension Low vapor pressure High specific heat capacity High heat of vaporization High boiling point Ice is less dense than water 17-1 17-2

Surface Properties 1. Surface tension = inward force, or pull, that tends to minimize the surface area of a liquid. Due to the hydrogen bonding (attraction) between water molecules. Water has HIGH surface tension, holds drops in a spherical shape. Surfactant = wetting agent, soap or detergent, that decreases surface tension (interferes with H-bonding) 2. LOW vapor pressure; hydrogen bonds keep water in liquid form from escaping into gaseous form.

Specific Heat Capacity 3. Specific Heat Capacity (C) = it takes 4.18 J (1 cal) of heat energy to raise the temperature of 1g of water 1°C. Due to hydrogen bonding, water has a HIGH specific heat capacity Cwater = 4.18 J/(g°C) C = Q = heat (J or cal) m x ΔT mass (g) x (°C)

Water Vapor and Ice 17-2

Evaporation + Condensation Heat of Vaporization = amount of E needed to convert 1g of a substance from liquid to gas at the boiling point. Water has a HIGH heat of vaporization due to H-bonding Heat of Vaporization = Heat of Condensation Hvap of water = 2.26 kJ/g or 2260 J/g Hfus of water = 334 J/g Phase change use: H = m x Hvap/fus Temp. change use: H = m x ΔT x C

Remember… When to use which H equation: Temp. Change Phase Change H = m x ΔT x Csteam Exothermic H = m x Hvap 100°C Temperature (°C) H = m x ΔT x Cwater H = m x Hfus 0°C Endothermic H = m x ΔT x Cice Heat Energy

Boiling Point Usually molecular compounds with a low molar mass have a low boiling point. 5. Water has a HIGH boiling point due to hydrogen bonding!

Ice Typically the density of a solid is greater than it’s liquid. 6. Ice is less dense than water! Hydrogen bonding holds water molecules in a rigid framework, crystallize (spaced far apart – larger volume, less dense) As it melts the framework collapses (closer together, more dense).

Aqueous Solutions 17-3

Solvents + Solutes Aqueous solution = water containing dissolved substance. Solute = dissolved particle. Solvent = dissolving medium; always water in an aqueous solution. Ionic compounds + polar covalent molecules dissolve easily. Nonpolar covalent molecules do not dissolve easily.

The Solution Process Solvation = the process that occurs when a solute dissolves. Ionic + Polar = negative and positive ions or poles are attracted to different regions of water molecule and are pulled apart. “Like dissolves like” – Ionic + polar substances can dissolve together. Ex: salt water (NaCl is ionic; water is polar). Nonpolar and nonpolar substances can dissolve together. Ex: gasoline + oil dissolve together, both are nonpolar!

Why don’t oil + water mix??

Electrolytes + Nonelectrolytes Electrolytes = compounds that conduct electric current in aqueous solutions or in a molten state. ALL ionic compounds and most polar molecules are electrolytes. Nonelectrolytes = compounds that do not conduct electric current in either aqueous or molten state. Many molecular (nonpolar) compounds are nonelectrolytes since they are not made up of ions

Weak electrolyte = only a fraction of solute exists as ions in solution (not dissolve completely, usually polar). Ex: HgCl2, NH3, sugar Strong electrolyte = almost all of solute exists as separate ions in solution (dissolves completely, usually ionic). Ex: NaCl, HCl, KCl

Water of Hydration Water of Hydration = the water in a crystal. Hydrate = a compound that contains water of hydration. Ex: CuSO4(aq)  CuSO4•5H2O(s) blue liquid blue crystals (hydrate) CuSO4•5H2O (s)  CuSO4(s) + 5H2O(g) white anhydrous powder evaporates heated

CuSO4(s) – Anhydrous Copper CuSO4•5H2O(s) Copper (II) Suflate Pentahydrate CuSO4(s) – Anhydrous Copper (II) Sulfate

Energy Source + Global Warming Pollutant Methane hydrate… a solid form of water that contains a large amount of methane within its crystal structure [that] occur both in deep sedimentary structures, and as outcrops on the ocean floor. “Fire Ice” Energy Source + Global Warming Pollutant

Hydrate Formula Writing a hydrate formula: Name of compound, Prefix (# of water) “-Hydrate” Ex: MgSO4•7H2O Magnesium sulfate heptahydrate Ex: Ba(OH)2•8H2O Barium hydroxide octahydrate Ex: Sodium sulfate decahydrate Na2SO4•10H2O Ex: Calcium chloride dihydrate CaCl2•2H2O Writing an anhydrous formula: Ex: MgSO4•7H2O(s) MgSO4(s) + 7H2O(g)

Hydrates Hydrates lose or gain water easily because forces keeping them together are weak. A hydrate which evaporates easily will effloresce – lose water of hydration Hydrate  Anhydrous Hydrates that remove water from air easily (gain water) are called hygroscopic Anhydrous  Hydrate Used as drying agents – dessicants.

Deliquescent compounds remove sufficient water from the air to dissolve completely and form solutions!

% Mass % Mass = grams part x 100% grams whole Ex: Calculate the % mass of water in CuSO4•5H2O. % mass of water = 5H2O x 100% CuSO4•5H2O = 90g x 100% = 36.0% water 249.6g

Heterogeneous Aqueous Systems 17-4 NO CLASS IS DOING THIS SECTION!!

Suspensions This chapter has focused on homogeneous solutions, now we will look at heterogeneous mixtures. Suspensions = mixture from which particles settle out upon standing. Particles are fairly large Can be separated through filtration.

Colloids Colloids = heterogeneous mixture containing particles of intermediate size. Can be in solid, liquid, or gas phase Ex: glue, gelatin, paint, aerosol sprays, smoke Do not settle out with time and cannot be separated by filtering. Exhibit Tyndall effect, scattering of visible light in all directions. Brownian motion = chaotic movement of colloidal particles; caused by collisions of particles with water molecules – prevents particles from settling!

Tyndall Effect

Brownian Motion