JANUARY 29

(Kristina)

JANUARY 27

(alanna)

January 25,2010

Today in class, Mr. Doktor went over any questions from the last homework.
MASS TO MASS & OTHER CONVERSIONS
Example.
Lead(IV) nitrate reacts w/5.0 g of potassium iodide. How many grams of lead(IV) nitrate are required for a complete reaction.
Pb(NO3)4 + 4KI -> PbI4 + 4KNO3

5.0g x 1 mole/ 166g x 1 mole/4 KI x 4 55.29/1 mole Pb(NO3)4 = 35g

2)How many grams of O2 are produced from the decomposition of 3.0g of potassium chlorate?
2KClO3 -> 2KCl + 3O2

3.0g x 1mole/122.6g x 3 mol O2/ 2 mole KClO3 x 33g/ 1 mole O2 = 1.2 g

3) If a 100mL solution of 2.0M(mol/L) H2SO4 is neutralized by solution hydroxide. What mass water is produced.
H2S04 + 2NaOH -> 2HoH + Na2SO4

0.100L x 2.0 mole/ L = .200 mole

.200mole H2SO4 x 2 mole HOH/ 1 mole H2SO4 x 18.0g/1mole = 7.2 g

% yield

• Theorteical yield of a reaction is the quanitity of producits expected
• The amount produced in an experiement is teh actual yield

The percent yield is:
% yield = actual/theoretical x 100

Example
The production of urea CO(NH2)2 is given by
NH3 + CO2 -> CO(NH2)2 + H20

47.7 g of urea are produced, determine
a)Theoretical yield if 1 mol of CO2 reacts
1.0 mole CO2 x 1 CO(NH2)2/1 CO2 x 60.1g/1mole = 60.1g
b) actual yield
47.7g
c)percent yield
47.7g/60.1g x 100 =

HOMEWORK

Gravimetric stoichiometry # 15-20 & extra stoichiometry problems worksheet

JANUARY 19

(Kristina)

JANUARY 13

In the beginning of class we corrected our homework from last days class (ask mr. Doktor for the answer key)

here are the notes mr. Doktor wrote on the board.

EXAMPLE #1

EXAMPLE #2

See mr. Doktor for our homework (worksheet) :

Enthalpy and Heat of Combustion

also be prepared to do a lab next class!

January 11

To start class off we corrected the classifying chemical equations and another worksheet. Mr. doktor did a demonstration on burning steel wool and magnesium. When Mr.doktor burnt the steel wool, the part that was in the fire was darker then the rest because the burnt wool was ion oxidized and it does not burn. When he burnt the magnesium, it looked like fireworks, it was very bright. He also passed around ammonia nitrate, he told the class that this was the stuff that is in the heat packs.

Heat in Chemical RxNs

• Reactions that release heat are exothermic
• Reactions that absorb heat heat are edothermic

Heat is a form of energy. All chemicals have stored energy called enthalpy

Enthalpy of water < align="left">

January 7

January 5

Today in class we learned about the different types of reactions.
SYNTHESIS
A + B = AB
ex. Al + F2 -> AlF3

DECOMPOSITION
AB -> A + B
ex. H3PO4 -> H2 + P4 + O2

SINGLE REPLACEMENT
A + BC -> B + AC
ex. Ca + KCl -> K + CaCl2

DOUBLE REPLACEMENT
AB + CD -> AD + CB
ex. MgCl2 + K2SO4 -> MgSO4 + ClK

NEUTRALIZATION
Acid + base -> Water + Ionic salt
ex. H2S04 + KOH -> HOH + K2SO4

COMMBUSTION
* reaction with oxygen
ex. C8H18 + 02 -> Co2 + H2O