AP CHEMISTRY EXAM QUESTIONS 3

AP CHEMISTRY EXAM QUESTIONS 3

• What is another name for transition state?: Activated complex

-in the middle

• The energy of activation (Ea) is the difference between...: -the energy of the starting materials (the reactant) and the energy of the transition state (the top point/the middle) • The energy change (Delta E) is the energy difference between...: -the starting materials (the reactants) and the products • Can Delta E be + 0r -?Can Ea be + or -?: Delta E can be positive or negative but activation energy is always positive • How do you find the Delta E for a certain reaction?: You subtract energy of the reactants from the energy of the products -Product minus Reactant • How do you find the Ea for a certain reaction?: You subtract energy of the reactants by the transition state (top) -Transition state minus Reactant • What substances are present in the reaction mixture when equilibrium has been obtained?3H(2) + N(2) <----> 2NH(3)

and why?: -H(2)

-N(2)

-NH(3)

-both products and reactants are being produced and consumed at the same rate -this is chemical equilibrium -equilibrium reactions always have some concentration of each substance present because the reaction is never completed in either direction -the production of either products or reactants may be favored but none of the chemicals in the reaction will be completely consumed • What are the 7 diatomic elements?: -Hydrogen: H(2)

-Nitrogen: N(2)

-Oxygen: O(2)

-Chorine: Cl(2)

-Iodine: I(2) 1 / 2

-Bromine: Br(2)

-(Have No Fear Of Ice Cold Beer) • Write a balanced equation for the decomposition of aluminum chloride into its elements -how do you know how to find the subscript numbers?: 2AlCl(3) ---> 2Al + 3Cl(2)

-to find subscript numbers: s from periodic table left to right it goes: +1, +2, +3, blank,

-3, -2, -1

So it's Al +3 and Cl-1 and you just criss cross the numbers 34. 2KClO(3) ----> 2KCl + 3O(2) If this reaction produced 81.6 g of KCl, how much O(2) was produced in grams?: -First start by converting mass of KCl to moles using molar mass of KCl -grams to moles, moles to moles, moles to grams -for moles to moles, look at equation and use the big numbers from there -whatever was in the first part of the line, put it on the bottom. So if KCl was the first thing written, put it on bottom next and put O(2) on top

-answer: 52.32 grams of O(2)

• When a question asks what the maximum mass/amount, what does that mean?: Maximum amount= the smaller answer of the 2 equations

• Limiting reactant: -limits the amount of product that can form

• How do you read an energy/reaction progress chart?: -from left to right

-reactions on the left -products on the right

• Where is Delta E and what does it mean/stand for?: -beginning of reaction

-the reactants have some amount of potential energy (E) -it means the energy difference between reactants and products (the difference in energy between the reactants and the products) • Which line represents the catalyzed reaction?: The bottom line because it has a lower activation energy

• Where is the Transition State?: Transition state is the top bump

-in the middle of reaction • Where is the Ea and what does it mean/stand for?: -needed to form from the transition state

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