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Unit 1- States of matter and the size of atom. Remembering the first day of school. “Knowing the volume of the gases would be helpful.” anonymous chemistry student How can we determine the volume of an unpressurized gas?. Particle diagram illustrating density.
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Remembering the first day of school “Knowing the volume of the gases would be helpful.” anonymous chemistry student How can we determine the volume of an unpressurized gas?
Particle diagram illustrating density What substance has the greatest density and how do you know? A B A B
Water is Weird Key Concept 1: Water is weird because water is the only substance that is more dense in a liquid state than in a solid state.
Key Concept 2: Desk Pod Discussion Questions • To determine the density of carbon dioxide what variables would we need to collect? • Should this experiment be done in an open or closed system? Explain why? • How can we determine the mass of the carbon dioxide produced? • How can we determine the volume of carbon dioxide produced?
Carbon Dioxide Accepted Values The accepted value of the density of carbon dioxide gas is 0.002 g/ml. The accepted value of dry ice (solid carbon dioxide) is 1.5 g/ml.
Particle Diagram for States of Matter Key Concept 3:
Quick Demos Demo 1: Carbon dioxide vs. Air Density: CO2 Air Physical Property:Chemical Property: • A physical property is an aspect of matter that can be observed or measured without changing it. Examples of physical properties include color, molecular weight, and volume. • A chemical property may only be observed by changing the chemical identity of a substance. This property measures the potential for undergoing a chemical change. Examples of chemical properties include reactivity, oxidation states and flammability.
Quick Demos Demo 2: ? vs. Air Density: ? Air Physical Property:Chemical Property: Draw a simple particle diagram to represent this demo. Demo 3: Hexane vs. Air Density: C₆H₁₄ Air Physical Property:Chemical Property:
Conversion Factors What is on your card? Key Concept 4: A conversion factor is a numerical factor used to multiply or divide a quantity when converting from one system of units to another.
Dimensional Analysis or Factor– Labeling • Key Concept 5: Dimensional analysis was developed to keep track of units in multi-step conversion problems (also known as factor-label method). • In the method, conversion factors are set up in fraction form. The equalities are then lined up sequentially and units used on the top and bottom of neighboring fractions are alternated so that units cancel. • In groups write your • conversion factor as a fraction.
Dimensional Analysis For example, consider the conversion of inches to centimeters (1.00 in = 2.54 cm). Write this conversion factor 6 different ways. How many centimeters are in 5.00 inches?
Key Concept 6: Hide Conversion Factors = Sign The word per The word for The word in How many conversion factors can you find on the back of your Periodic Table? How many sig figs do conversion factors have?
When is dimensional analysis useful? A batch of French toast requires 3 eggs to make. How many eggs are needed to make 8 batches? The same French toast recipe can feed 4 people per batch. If you throw a breakfast party for 12 people, how many batches do you need to make?
When is dimensional analysis useful? Nonsense words taken from the poem Jabberwocky by Lewis Carroll There are 20 tumtum trees in the tulgey wood. In each tulgey wood is one frumious Bandersnatch. There are 5 slithy toves in 2 borogoves. There are 2 mome raths per Jabberwock. There are 2 Jubjub birds in 200 tumtum trees. There are 200 mome raths in each borogove. There are 5 Jubjub birds per slithy tove. The question is: If there are 5 frumious undersnatches, how many Jabberwocks are there?
When is dimensional analysis useful? You are a veterinarian’s assistant. The doctor asks you to give Lassie, a young girl’s dog, 18.5 mg of Acepromazine before it goes into surgery. However, the medicine is in liquid form and must be given intravenously. Reading the bottle you see that Acepromazine has a density of 10mg/ml. How many mL of Acepromazine should you give the dog?
Chemistry Conversion Factors 1 cm3= 1 ml Density: __ g = __ ml 1 mole = 6.02 x 1023 particles 22.4 L of a gas = 1 mole 1 mole = molecular mass of a compound ___ mole of A= ___ moles of B
When is factor labeling useful? In a spacecraft, the carbon dioxide exhaled by astronauts can be removed by its reaction with lithium hydroxide, LiOH, according to the following chemical equation. CO2(g) + 2LiOH(s) Li2CO3(s) + H2O(l) How many moles of lithium hydroxide are required to react with 20 mol of CO2, the average amount exhaled by a person each day?
Converting Units (cont) Factor Labeling Step Determine what the question is asking you to solve for. Determine what is given in the problem to be converted. Identify and plug in the appropriate conversion factors as fractions (unit on top need to match the unit on bottom). Cancel units Verify your answer. (Units must match units in step 1. If the answer doesn’t match, repeat 3 and 5).
Converting Units (cont) Key Concept 7: Factor Labeling Step ? Asking Given Plug in the appropriate conversion factors (unit on top need to match the unit on bottom) Cancel units Verify your answer
Practice Example Key Concept 8: A car is traveling 65 miles per hour. How many feet does the car travel in one second?
Density Calculations Key Concept 9: What is the weight of the ethyl alcohol that exactly fills a 200.0 mL container? The density of ethyl alcohol is 0.789 g/mL. A block of aluminum occupies a volume of 15.0 mL and weighs 40.5 g. What is its density?
Thickness of Aluminum Foil • Goal: How thick is regular aluminum foil vs. heavy duty foil. • Through unit 1 you have developed the skills need to determine the thickness of Aluminum Foil. • Density of Aluminum is 2.7g/cm3
Thickness of Aluminum Foil • Working as lab tables. • Each lab table will have to make a plan of action on their whiteboards. • Mrs. Askew and Ms. Lieber must approve. • Copy plan into lab notebook • Determine thickness. • Class Result
Class Data • Accepted Value Regular= 1.6 x10-3 cm Heavy Duty= 2.4 x 10-3 cm
Thickness of Aluminum Foil • Particle Diagrams • How many atoms thick is it? • The accepted diameter of Al atom is 2.9x 10-8 cm.