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Element of the Day
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GdGadolinium (gadolineeәm) is a chemical element with the symbol Gd and atomic number 64. It is a silverywhite, malleable and ductile rareearth metal. It is found in nature only in combined (salt) form. The metal was isolated by Lecoq de Boisbaudran in 1886.
Gadolinium metal possesses unusual metallurgic properties, with as little as 1% of gadolinium improving the workability and resistance of iron, chromium, and related alloys to high temperatures and oxidation. Gadolinium as a metal or salt has exceptionally high absorption of neutrons and therefore is used for shielding in neutron radiography and in nuclear reactors. Like most rare earths, gadolinium forms trivalent ions which have fluorescent properties. Gd (III) salts have therefore been used as green phosphors in various applications.Question: Name this compound: GdF3
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Chemistry1. Element of the Day Gd 5 (5)2. Continue Lecture (20)3. Finish Iron Copper Lab (25)4. Start Homework
AnnouncementsDue Today: Read pages 251 259 and answer questions 17, 18, 19, 26, and 31.
Due Thursday: Complete Iron Lab
Need Empirical Formula and Molecular Formula POGIL Activity from some of you I mistakenly passed it back to you beofre entering grades
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Review Homework
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Mole Mole Relationships
Aim: To learn to use a balanced equations to determine relationships between moles of reactants and moles of products.
Lecture Notes: Chemical Quantities
Given the equation:
2H2O(l) > 2H2(g) + O2(g)
This equation means:
1. How many moles of O2 are produced if we start with 20 moles of H2O?
2. How many moles of O2 will be produced by the decomposition of 10.1 moles of water?
Mole ratio:
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Lecture Notes: Chemical QuantitiesSteps for Calculating the Masses of Reactants and Products in Chemical Reactions
1. Balance the equation for the reaction.
2. Convert the masses of reactants or products to moles.
3. Use the balanced equation to set up the appropriate mole ratio(s).
4. Use the mole ratio(s) to calculate the number of moles of the desired reactant or product.
5. Convert from moles back to masses.
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Lecture Notes: Chemical Quantities
Example Problem 2
Thionyl chloride, SOCl2, which is used as a drying agent in many synthetic chemistry experiments, reacts with water to form sulfur dioxide gas and hydrogen chloride gas.
A. Calculate the mass of water consumed by the complete reaction of 3.50 x 102 grams of thionyl chloride.
B. Calculate the mass of hydrogen chloride produced by the complete reaction of 3.50 x 102 grams of thionyl chloride.
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Lecture Notes: Chemical QuantitiesCalculations Involving a Limiting Reactant
Learning Target: Recognize the limiting reactant in a reaction and to learn to use the limiting reactant to do stoichiometric calculations.
Ammonia, which is a key ingredient in fertilizer, is made from combining hydrogen gas with nitrogen gas. We synthesize hydrogen gas by combining methane gas and water vapor. Carbon monoxide is a byproduct of this reaction.
What mass of water is required to react exactly with 259 g. of methane?
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Lecture Notes: Chemical QuantitiesCalculations Involving a Limiting Reactant
Learning Target: Recognize the limiting reactant in a reaction and to learn to use the limiting reactant to do stoichiometric calculations.
Ammonia, which is a key ingredient in fertilizer, is made from combining hydrogen gas with nitrogen gas. We synthesize hydrogen gas by combining methane gas and water vapor. Carbon monoxide is a byproduct of this reaction.
In the previous problem, what if we used 500 grams of water instead? Then the ______________ will be consumed before the water runs out. The water would be in _____________. In this situation, because the amount of methane limits the amount of products that can be formed, it is called the ________________, or __________________.
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Lecture Notes: Chemical QuantitiesCalculations Involving a Limiting ReactantSteps for Solving Stoichiometric Problems Involving Limiting Reactants1. Write and balance the equation for the reaction.
2. Convert known masses of the reactants to moles.
3. Using the numbers of moles of reactants and the appropriate mole ratios, determine which reactant is limiting.
4. Using the amount of the limitng reactant and the appropriate ratios, compoute the number of moles of the desired product.
5. Convert from moles of the product to grams of the product, using the molar mass (if this is required by the problem).
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Lecture Notes: Chemical QuantitiesCalculations Involving a Limiting Reactant
Aluminum reacts with chlorine gas to form aluminum chloride.
In a certain experiment, 10.0 grams of aluminum is reacted with 35.0 grams of chlorine gas.
Questions1. What mass of aluminum chloride will be produced assuming a complete reaction.
2. What mass of the reactant in excess is left after the reaction?
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Iron Copper Lab
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ReminderDue Thursday: Complete Iron Lab
Exit QuestionWhat is a limiting reactant?
