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 ml of water 2. Heat Until Boiling 3. Make Three marks on test tube 1cm apart

Reaction # 1 Cu(SO 4 ) + 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 bath 2. Turn off heat and Remove from beaker after no more change occurs. 3. Record Observations

Reaction # 3 1. Add 1 M HCl to third mark 2. Mix with stirring rod 3. Record Observations

Reaction # 4 1. Add Aluminum wire to test tube 2. Record Observations

Copper (II)Sulfate + Sodium Hydroxide  CuSO 4 + NaOH 

Copper Hydroxide + Heat  CuOH 2 

Copper Oxide + Hydrogen Chloride  CuO + HCl 

Copper Chloride + Aluminum  CuCl 2 + 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 x 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. Amadeo Avogadro molecules

Size of an atom gin/cells/scale/ gin/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 minutes 1 minute = 60 seconds 1 hour = 3600 seconds 1 mole = x 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: x mole Atoms, ions, particles, molecules  Moles then use: 1 mole x 10 23

Determine the number of atoms present in 2.0 mol of carbon? What do you know? Amount of Carbon= 2.0 moles Number 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 atoms of Copper?

Atoms  Moles How many moles of Xenon is 5.66 x atoms of Xe? How many moles of Nitrogen is x 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