Transcript Chemistry Lab Safety Rules

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
What substance has the greatest density and
how do you know?
A
B
A
B
Particle diagrams of state of matter?
Particle diagram illustrating density
Water is Weird
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.
What gas could we use?
Key Concept 2: Desk Pod Discussion Questions
1. To determine the density of carbon dioxide
what variables would we need to collect?
2. Should this experiment be done in an open
or closed system? Explain why?
3. How can we determine the mass of the
carbon dioxide produced?
4. How can we determine the volume of carbon
dioxide produced?
Class Data
Lab Table
1
2
3
4
5
6
7
Mass of CO2 (grams)
Volume of CO2 (ml)
Density (g/ml)
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
Physical Property:
Air
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?
Write conversion factors as fractions.
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
1. Determine what the question is asking you to solve for.
2. Determine what is given in the problem to be converted.
3. Identify and plug in the appropriate conversion factors as
fractions (unit on top need to match the unit on bottom).
4. Cancel units
5. 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
1. ? Asking
2. Given
3. Plug in the appropriate conversion factors (unit on
top need to match the unit on bottom)
4. Cancel units
5. 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
Lab Table
Thickness of regular
Thickness of heavy duty
1
2
3
4
5
6
7
• 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.