Evidence of Chemical Change Laboratory

Shawn Fausey

Goals for the Day

Observe evidence that a chemical change has occurred:

Energy is involved, color change, precipitate formed, evolution of gas

Identify and Record these Observations Describe reactions by writing word

equations Complete the laboratory observations,

analysis, and conclusions

Lab Safety Rules

Always wear safety goggles and a lab apron to protect your eyes and clothing

Do not touch any chemicals Call your teacher in the event of a spill Never put broken glass in a regular waste container Do not heat glassware that is broken, chipped, or

cracked CAUTION!!! NaOH & HCl – Location in the Lab Points will be deducted if your lab goggles or

apron is removed at anytime throughout the lab.

Key Vocabulary

Soluble-Insoluble-Elements-Compounds- Energy-

Make Water Bath

1. 50 ml of water 2. Heat Until Boiling3. Make Three marks on test tube 1cm

apart

Reaction # 1 Cu(SO4) + NaOH -->

Add 1 M Copper Sulfate to first line

Add 1 M NaOH to second line

Mix solutions using glass stirrer

Record Observations:

Reaction # 2

1. Place test tube in water bath2. Turn off heat and Remove from

beaker after no more change occurs.3. Record Observations

Reaction # 3

1. Add 1 M HCl to third mark2. Mix with stirring rod3. Record Observations

Reaction # 4

1. Add Aluminum wire to test tube2. Record Observations

Copper (II)Sulfate + Sodium Hydroxide

CuSO4 + NaOH

Copper Hydroxide + Heat

CuOH2

Copper Oxide + Hydrogen Chloride

CuO + HCl

Copper Chloride + Aluminum

CuCl2 + Al

Hydrogen Chloride + Aluminum

HCl + Al

Counting Atoms

Does anyone know how atoms are counted and measured?

No, do we lay them out on the table and count them one by one? Why not?

Why can’t we just dump some carbon atoms out on the table and count them?

What chemists did?

As we know atoms are extremely small, so small that we can’t see them and for convenience chemists created a unit to express the amount of a substance.

That unit is called the:

Mole, and it is defined as the number of atoms in exactly 12 g of carbon-12.

Avogadro’s Number

The number of particles in a mole is called Avogadro’s constant or number.

The constant is 6.0221367 x 1023 per mole.

Amadeo Avogadro was an Italian physics professor who proposed in 1811 that equal volumes of different gases at the same temperature contain equal numbers of molecules.

Size of an atom

http://learn.genetics.utah.edu/content/begin/cells/scale/

Molar Mass

1 mole of any element on the periodic table is equal to that elements molar mass.

Units of Measurement

Counting Units 1 dozen = 12 Objects 1 hour = 60 minutes1 minute = 60 seconds1 hour = 3600 seconds1 mole = 6.022 x 1023 atoms, molecules,

elements, ions, electrons

Simple Unit Conversions

20 Dozen x _______= eggs 240 eggs x _______= dozen

2 hours x ______ = minutes

120 min x ______ = hours

Converting from moles to atoms and atoms to moles

Moles Atoms, ions, particles, molecules then use: 6.022 x 1023

1 mole

Atoms, ions, particles , molecules Moles

then use: 1 mole

6.022 x 1023

Determine the number of atoms present in 2.0 mol of carbon?

What do you know? Amount of Carbon= 2.0 molesNumber of Carbon atoms = ?

Moles Atoms

How many atoms are present in 3.7 mol of Sodium?

How many atoms are present in 155 mol of Arsenic?

How many moles are in 4.5x 1020 atoms of Copper?

Atoms Moles

How many moles of Xenon is 5.66 x 1026 atoms of Xe?

How many moles of Nitrogen is 6.022 x 1023 atoms of Nitrogen?

Tonight in your notebooks:

Classify each chemical reaction as single displacement, double displacement, or synthesis.

Balance the chemical equations.Write the phases gas, solid, and liquid

for each compound from the reactions.

Finding what we want….

Atoms

Grams

Moles