Transcript Classic Butter Cookies 2 1/2 cups all

Classic Butter Cookies
2 1/2 cups all-purpose flour
1 cup butter
1/2 cup white sugar
2 eggs
1/2 teaspoon almond extract
Bake at 350ºF for 10 minutes.
Yields 20 3” cookies
1. If only one egg was available, but as much of the other ingredients as you needed,
how many cookies would you make?
2. If 4 eggs were available, how many cookies could you make if you had all of the
other ingredients? How much flour would you need?
3. If 40 3” cookies were baked, how many cups of flour were used?
Stoichiometry
The study of the quantitative, or
measurable, relationships that
exist in chemical formulas and
chemical reactions.
Write a reaction for the combustion of
glucose, C6H12O6
1.If two moles of glucose reacts with an excess
of oxygen, how many moles of water are
produced?
2. If 3 moles of carbon dioxide are produced,
how many moles of glucose were consumed
(used)?
3. How many moles of oxygen are needed to
completely react with 1.94 moles of glucose?
Mole ratio
• Ratio of moles of one substance to
another
• Determined from coefficients in the
balanced chemical equation
• Write all possible mole ratios for the
combustion of glucose
DO NOW
• What is the “recipe” that we use in
stoichiometry?
Balanced chemical equation
• What are the quantities expressed in
the “recipe”?
Moles!
• In solving stoichiometry problems,
what unit equality allows us to convert
from one substance to another?
The mole ratio
Review of Mole-mole Problem
• Hydrogen and oxygen gases react to
produce water.
• If 59.84 moles of water is produced,
how many moles of oxygen gas must
be used?
Do NOW!
Write a reaction for the synthesis of
ammonia, NH3, from nitrogen and
hydrogen gases.
A)If 5.23 moles of ammonia is
produced, how many moles of
hydrogen reacted?
B)If an excess of nitrogen is reacted
with 3.41 g of hydrogen, how many
grams of ammonia are produced?
How many grams of sulfur
trioxide will be produced from the
reaction of 45.0 g of sulfur with an
excess of oxygen?
MASS-MASS PROBLEM
Mass A -> Moles A -> Moles B -> Mass B
1)Divide
by molar
mass of A
2)Use
mole ratio
3)Multiply
by molar
mass of B
What volume of oxygen gas is
required to oxidize 4.99 g of
NO gas to NO2 gas?
(Assume STP)
Type of problem? Volume-Mass
But you are responsible for any…
Moles- mass-particles-volume
So remember your conversion factors
Conversion Factors
• 1 mol = 22.4
L
• 1 mol = 6.02 x 1023 particles
(molecules, atoms, formula units)
• 1 mol = (molar mass) g
From periodic table
Types of problems
•
•
•
•
•
Mole –Mole ( 1step)
Mass – Mass ( 3 steps)
Volume- Volume ( 3 steps)
Mass-Volume ( 3steps)
Volume – Mass (3 steps)
• Label Given and unit of
answers immediately!!!!
1. Balanced chemical equation
2. Convert given to moles
3. Use mole ratio
4. Convert moles to answer
Magnesium reacts with hydrochloric acid
to produce magnesium chloride and
hydrogen gas
1. If 6.00g of hydrochloric acid reacts with an
excess of magnesium, how much
magnesium chloride will be produced?
• 2. If 10.0 grams of magnesium chloride is
actually produced, what is the percent
yield?
ACTUALLY/EXPERIMENTALLY made
Percent
Yield
= Actual Yield
x 100
Theoretical Yield
Based on STOICHIOMETRY
Why does actual = theoretical,
sometimes?
• Reaction may not go to completion
• Competing reactions may reduce the
yield of product
• Material may be lost in handling
Classic Butter Cookies
2 1/2 cups all-purpose flour
1 cup butter
1/2 cup white sugar
2 eggs
1/2 teaspoon almond extract
Bake at 350ºF for 10 minutes.
Yields 20 3” cookies
Limiting
Reactant
Excess
Reactant
If I have 2 eggs, 2 cups of butter, and
an excess of all the other ingredients,
how many cookies will I make?
Iron metal can be produced by reacting
iron ore (Fe2O3) with carbon. Carbon
monoxide is also produced.
1.Write a balanced chemical
equation for this reaction.
2.If 50. grams of carbon is reacted
with 150 g of iron III oxide, how
many grams of iron are
produced?
Sodium metal and chlorine gas
produce sodium chloride.
1. How many grams of sodium chloride are
produced if 15.9 L of chlorine gas, at
STP, reacts with an excess of sodium?
2. What is the percent yield if 58.3 grams of
sodium chloride is produced?
3. In a separate experiment, 25.0 g of
sodium reacts with 55.0 g of chlorine,
how many grams of sodium chloride are
produced? What is the limiting reactant?
How much excess reactant remains?