160 likes | 359 Views
Happy November Scientists!. Warm-Up: What is the difference between an atom and a molecule? Return work/update portfolios Element Exploration Share/Reflection Turn in Element Exploration and Card Chemistry Demo/Inquiry 2: Electrical Current and Water. Li.
E N D
Happy November Scientists! Warm-Up: What is the difference between an atom and a molecule? Return work/update portfolios Element Exploration Share/Reflection Turn in Element Exploration and Card Chemistry Demo/Inquiry 2: Electrical Current and Water
Li • Atom: the smallest amount of an element that still has all the properties of the element • Molecule: made of 2 or more atoms
Chemistry Demo/Inquiry 2: Electrical Current and Water • Focus Question: What is the effect of an electrical current on a solution of salt and water? • Hypothesis: I think… because… • Observations:
Materials manager • Collect: • Cup of liquid • Two pencils attached to a battery
Place the ends of the pencils in the water. • Record your observations
Materials manager • Collect two wires with alligator clips • Connect the wires as shown in the diagram • Place the ends of the pencils in the water • HOLD THE PENCILS IN THE WATER • Do not let the pencils rest on bottom of the cup. • Record your observations
Reflection • Is this a chemical reaction? • What is your evidence? • How can you explain your observations? (What do you think is happening?)
What we know for sure… • An electrical circuit was completed • Energy was put through the water • Bubbles were produced • More bubbles were produced on one pencil than on the other.
What is happening? • Water + salt + electric current bubbles • 2H2O + electrical current 2H2 + O2 • Would this happen without the electric current? • So…the atoms of Hydrogen and Oxygen are being held together by something that requires energy to break it – this is called a chemical bond.
It’s Wednesday! Welcome to Science! Today: Chemistry Demo 3: Potassium Chlorate + Sulfur Record your observations as Mrs. Ellis Demonstrates Review the last lesson Introduction to Chemical Bonding
Observations • BEFORE • DURING • AFTER
Whoa, what was that? • Potassium Chlorate and Sulfur and grinding yields heat, sound and odor and a black solid • This happens in 2 reactions: First: The grinding makes heat (friction) which triggers: • KClO3 KCl + 3On • (the n means the oxygen is in free atoms which are very reactive) Then: The oxygen attacks the sulfur and produces a lot of SO2 gas very quickly (causing a pressure wave = sound) • S + 2On SO2 • (the SO2 gas is the odor you observed)
What happened last time? • Water + salt + electric current bubbles • 2H2O + electrical current 2H2 + O2 • So…the atoms in both reactions are being held together by something that requires energy to break it – this is called a chemical bond. • Chemical Bond: an attraction between atoms that allows molecules to form
Next…make a T-chart: Read Pages 4 – 7 in your textbook and record important chemistry vocabulary in the appropriate column in you table
Re-Read pgs 4 - 7 • Write one sentence that summarizes each section which has a colored heading. (there are 8) • Mrs. Ellis will model the first paragraph • Then: • Tables 1 – 4 draw a sodium atom (Na) • Tables 6 – 9 draw a chlorine atom (Cl) • When Mrs. Ellis says to, find someone with a different atom than you – compare the atoms, what do you notice?
Now… • Everyone: • Draw a neon (Ne) atom • What do you notice? How is this atom different from Na and Cl? • Since it has a full outer shell, it is not reactive with other atoms because it has the “happy number”