3/15/12 – Bell ringer
description
Transcript of 3/15/12 – Bell ringer
![Page 1: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/1.jpg)
3/15/12 – Bell ringer• Water freezing or boiling is
not chemical reaction. Why?
• Hold on to 4 bell ringers as we will turn them in at the end of notes
![Page 2: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/2.jpg)
Chapter 23 – Chemical Reactions
23.1 – Chemical Changes
![Page 3: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/3.jpg)
Objectives• 1. Identify the reactants and products in
a chemical reaction.• 2. Determine how a chemical reaction
satisfies the law of the conservation of matter.
• 3. Determine how chemists express chemical changes using equations
![Page 4: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/4.jpg)
Chemical Reaction
• A change in which one or more substances are converted to new substances–Reactants – the substances that react–Products – the new substances
produced
![Page 5: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/5.jpg)
Different Reactions• Chemical reactions – use the
ELECTRONS to form new substances• Nuclear reactions - use the
NUCLEUS to form new substances
• What does a chemical reaction look like?
![Page 6: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/6.jpg)
Chemistry Kitchen
![Page 7: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/7.jpg)
Chemistry Kitchen
REACTANTS PRODUCTS
![Page 8: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/8.jpg)
Think about it…• If you burned a piece of paper, you end
up with a pile of ashes.• Once burned, is there…
– More mass?– Same mass?– Less mass?
• Why?
![Page 9: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/9.jpg)
Conservation of Mass• Law that states in a chemical
reaction, matter is not created or destroyed– Antoine Lavoisier experimented
with mercury (II) oxide and heat– He found mass of products (liquid
mercury and oxygen gas) equaled mass of reactants
![Page 10: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/10.jpg)
Chemical Equation• Uses chemical formulas and symbols to
describe a chemical reaction and the product(s) it produces– Chemical formula expresses the
relationship between elements in the compound and molecules they make up
![Page 11: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/11.jpg)
Chemical Equation
Reactants (left) → Products (right)Arrow means “yields”
SnO2(s) + 2 H2(g) → Sn(s) + 2 H2O(g)
CH4(g) + 2 O2
(g) → CO2(g) + 2 H2O(g)
![Page 12: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/12.jpg)
Coefficients• Numbers which represent the
number of units of each substance in a reaction– Knowing coefficients of chemical
reactions allows chemists to use the correct amount of reactants to predict the amount of products (law of conservation applies)
![Page 13: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/13.jpg)
Example
![Page 14: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/14.jpg)
Writing equations• Subscripts = Numbers which represent
the number of atoms in a molecule of a particular element
• Symbols used to show state of reactants–(s) solids–(aq) aqueous–(l) liquid–(g) gas
![Page 15: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/15.jpg)
Volcano with a Twist• Reactants?
• Products?
![Page 16: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/16.jpg)
• Equation:NaHCO3 ( ) + CH3COOH ( ) CH3COO-Na+ ( ) + H2O ( ) + CO2 ( )
• States?• Conservation?
![Page 17: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/17.jpg)
Exit slip on BR paper• SnO2(s) + 2 H2(g) → Sn(s) + 2 H2O(g)
• What are the reactants?• What are the products?• How is matter conserved/equalled out?• What changed?
– (Compounds and States)
![Page 18: 3/15/12 – Bell ringer](https://reader036.fdocuments.in/reader036/viewer/2022062323/56815f3f550346895dce14b6/html5/thumbnails/18.jpg)
In-class Assignment/Homework• 23.1 WKT