1B. Looking at Water & Its Contaminants Learning more about the chemistry of water and how substances interact with water
Do Now: (day 1) • Read Article on pg. 25 and write a paragraph summary addressing: • water tests that were performed • Concerns • Other important information
Do Now (cont.) Concerns Dissolved oxygen (DO) levels – will test Microorganisms – none present Dissolved matter – must consider amounts & effect of temperature on solubility – will test Suspended particles – will test Other Information No illness – water conservation tips – more water trucked in – 3 day crisis expected
Now what? Water experts agree that the fish kill was caused by something either dissolved or suspended in the Snake River. How can you determine the exact cause? Knowing properties of water & properties of substances that may be found in it will help. Knowing language of chemistry will help you communicate your findings. 4
Objectives • SWBAT compare and contrast surface tension between water and alcohol • SWBAT define matter and discuss the physical properties of water. • SWBAT calculate density
Mini- group activity- WKST U1B2 PREDICTION: How many drops of water can a penny hold without spilling over?
Water is very common… on Earth 70% of Earth’s surface covered by oceans – average depth of 3 km (2 mi) Unmatched by any planet or moon in our solar system 9
Matter • MATTER: IS ANYTHING THAT HAS MASS & OCCUPIES SPACE. • WATER IS MATTER.
Let’s think about… What states of matter can be observed in this winter scene?
Water has Physical Properties Matter can be distinguished by its properties. Physical properties are those can be observed and measured without changing the chemical makeup of the substance Ex.- color, odor, density, melting point, boiling point, freezing point. 12
Water has Physical Properties • Density – Water’s density is 1.00 g/cm3 or 1.00 g/mL at 25oC – varies by temperature • Ex. Mini-lab • Freezing Point – 0oC at normal atmospheric conditions • Any others? 13
Do Now (day 2) • What physical property of water explains the “sheeting action” under the swimmers right arm?
Objectives • SWBAT identify physical properties of substances • SWBAT differentiate between mixtures and substances and heterogeneous and homogenous mixtures • SWBAT create a concept chart of all types of solutions
Unit 1B.2 p2 • Think-Pair-Share WKST
“Pure” Water • “Pure” water is water with absolutely nothing else dissolved or suspended in it • Properties of pure water • Clear • Colorless • Odorless • Tasteless 17
Substances Dissolve in Water • Aqueous solutions – water based solutions • SOLUTE- substance that is being dissolved • SOLVENT- substance that dissolves the solute (usually water, in aqueous solutions it is water) 18
Matter is divided into a mixture or a substance • Mixture: • two or more substances coming together but keeping their individual properties • “Foul Water” was a mixture of water, used coffee grinds, oil, garlic powder, salt • Substance: • Definite composition, not physically able to separate
Types of Mixtures • Homogeneous Mixture: • Composition is the same or uniform throughout • Heterogeneous Mixture: • Composition is not the same or uniform throughout.
2 Types of Heterogeneous Mixtures Suspension – heterogeneous mixture containing large, solid particles that can settle out or be separated by filtration Colloid – heterogeneous mixture containing particles too small to settle out – cloudy – Tyndall effect 24
Solutions All solutions are homogeneous mixtures • A solute dissolves in a solvent to make a solution • Solutions are clear but not necessarily colorless • A conductivity test indicates the presence of dissolved charged particles 25
Types of Substances • Elements: • One type of atom • Compounds: • Two or more types of atoms chemically bonded together
Do Now • What are the two major types of mixtures? • What is the difference between a suspension and a colloidal dispersion?
Objectives • SWBAT review the differences between types of mixtures. • SWBAT create a concept chart of substances and mixtures and provide examples of each. • SWBAT differentiate between symbol, element, compound, and molecule.
Particulate Level To understand the macroscopic (large scale & readily observed) properties of water, you have to understand water’s behavior at the particulate level – the level of small particles – the level of atoms and molecules 31
Substances Atoms – “building blocks of matter” Elements – made of one kind of atom Represented by symbols (H, O, Ne) & sometimes formulas (H2, O2) Molecules – made of atoms joined together – atoms can be the same or different Compounds – made of different elements combined together Represented by formulas (H2O, KCl) 32
MODELS:REPRESENTATIONS OF ATOMS & MOLECULES These pictures are one kind of model (space filling model). 34
Models of Water “Seeing and Imagining Water” Visit the online site for 1B http://www.whfreeman.com/chemcomstudent/index2.html 35
1B.5 PICTURES IN THE MIND Modeling Matter 36
Drawing Models • Sample Problem: Draw a model of two gaseous compounds in a homogeneous mixture. • What do you need to know to draw your model? • What is a homogeneous mixture? • What might a gaseous compound look like? • How many compounds are in this mixture? • There is more than one drawing possible. 37
Do Now • Describe the picture: • 1. What type of mixture is this? • 2. How many compounds? • 3. What state of matter?
Objectives • SWBAT classify pictures as homogeneous, heterogeneous, gas, solid, or liquid. • SWBAT identity the number of different compounds in a substance or mixture • SWBAT draw different mixtures and answer questions related to those pictures
Drawing Models Which of the following drawings best represents a homogeneous mixtures of two gaseous compounds? 40
Drawing Models • Not homogeneous • 2 types of molecules are uniformly mixed • Atoms are colored to represent different elements • 3 different compounds, not 2 The best answer is “b.” “b” & “c” are space-filling models. “a” is a ball-and-stick model. Both are acceptable. 41
Drawing Models Finish the 7 questions for the B.5 Pictures in the Mind modeling matter activity on pp. 33-34. 42
Homework • Pg. 50 #1-4, 6-8, 10
Do Now • Name 4 elements • Where can you find each one?
Objectives • SWBAT understand the requirements for the mole day project • SWBAT determine numbers of atoms in a formula • SWBAT identify elements on the periodic table and understand how to write their symbols • SWBAT research and create a poster about a particular element
Symbols, Formulas, & Equations • The international language of chemistry includes symbols, formulas, & equations. • Symbols are like letters. • Formulas are like words. • Equations are like sentences. 47
The “letters”Symbols – Elements • Elements are organized on the Periodic Table of Elements • Each element is represented by a symbol • Capital letter • Capital letter & lower case letter • Find some of these symbols on the Periodic Table. 48
The Periodic Table of Elements contains much more useful information than just symbols.You will be learning more about this table throughout this course. People use aluminum to make a variety of products, including foil, cans, & lightweight construction materials. 49
Silicon has properties that lie between those of metals and nonmetals. It is classified as a metalloid. One of its primary uses is in electronic devices. 50