1.AP Chem AB FRQ
A sample consisting of 50. mL of 0.400 M solution of the acid, HClO4, is titrated
titrated with a 0.200 M solution of the base, LiOH.
Write the balanced chemical reaction for neutralization reaction:
HClO4 (aq) + LiOH (aq) → LiClO4 (aq) + H2O (l)
Write the NET ionic equation for the neutralization reaction.
OH⁻ (aq) + H⁺ (aq) → H2O (l)
Compute the pH of the titration solution. Show your work
i) before any of the base is added
ii) after 25. mL of base is added
iii) after 50. mL of base is added
A student performs the titration with the same chemicals but with smaller volumes of each chemical . Which of the following titration curves could represent the titration. Explain
A because this entails a strong acid and a strong base.
A student performs a titration of an unknown acid with a strong base and gets the following titration curve:
a) The student consults the list of pKa of acids shown below. If the acid is listed in the table below, which is the most likely identity of the unknown acid? Explain.
7.2 x 10-4
1.8 x 10-5
4.3 x 10-7
2.0 x 10-9
The unknown acid is HBrO because the calculated Ka is in between 50^-4 and 50^-6 and 2.0 x 10^-9 lies in between them.
b) What is the initial molarity of the acid?
10^-3 = 0.001M
a) Describe the components and the composition of an effective buffer solution. Explain how the components of the buffer allow the buffer to maintain its pH.
An effective buffer solution has a weak acid and its conjugate base or a weak base and its conjugate acid. A buffer solution is most effective when the ratio of its component concentrations is close to 1, also when the pH is equal to the pka of the acid.; The components of the buffer allow the buffer to maintain its pH because buffers can absorb excess H+ions or OH– ions.
An employer is interviewing four applicants for a job as a laboratory technician and asks each how to prepare a buffer solution with a pH of 5.0. The following constants may be helpful: hydrazoic acid, pKa = 4.74 Boric acid, pKa = 9.23
Archita A. says she would mix equal molar solutions of hydrazoic (HN3) and sodium azide (NaN3) solutions.
Bradley B. says she would mix equimolar Boric acid (H3BO3) and HCl solutions.
Carlos C. says he would mix equimolar Boric Acid (H3BO3) and sodium dihydrogen borate (NaH2BO3) solutions.
Delia D. says he would mix equimolar hydrazoic Acid (HN3) and NaOH solutions.
b) Which of these applicants has given an appropriate procedure? Explain your answer
Delia because she is using Sodium hydroxide which results in a pH of 5. NaOH is a strong base and in order to have an effective buffer a weak acid must be incorporated which is the HN3.
c) Explain what is wrong with the erroneous procedures.
The rest all incorporate a strong acid and a strong base or a weak acid and a weak base which don’ result in an effective buffer.
d) The applicants have access to the 1 Liter volumes of each of the solutions listed above. They have access to graduated cylinders. In order to make 1.0 Liter of the correct 5.0 buffer solution, what volumes of the two chemicals must be mixed?
2.At a price of $1.04 per roll, the supply of toilet paper in a large town is 25,000 rolls, and
mand is 18,200 rolls. When the demand increases to 26,200 rolls, the supply is 20,000 and the price is $1.24 per roll. Let x be the quantity in thousands of rolls. The table below gives the price-supply and price-demand equations.
Price Equations for Toilet Paper
Price-Supply P = -0.04x + 2.04
Price-Demand P = 0.025x + 1.495
Find the supply at a price of $2 per roll.
Find the demand at a price of $2 per roll.
Use the substitution method to find the equilibrium quantity. Round x to the nearest tenth first and then convert to thousands. Include the units in your answer.
What is the equilibrium price? Write the answer in dollars and cents, rounding to the nearest cent.
3.Hello I have two problems to solve the subject is Quantitative Methods for Decision-Making
After graduating from AUD, Salman plans
After graduating from AUD, Salman plans to start a book publishing company in the Media City. He did some research and found that the printer will cost Dh 230,000. He estimated that the variable cost per book is Dh 170 and the selling price is Dh 390.
a. How many books must he sell to break even? Also calculate the breakeven in dirham.
b. In addition to the costs given above, if he wants to pay himself a salary of Dh 15,400 per year, what is her breakeven point in units and dirham?
c. In the first three months of his business, he sold 400 books. Suddenly the printer breaks down. He spent Dh 25000 to fix the printer. In addition to 400 books sold, how many more books she should sell to breakeven? Assume that this part of the question is independent, and she does not draw any salary.
A furniture store makes tables and chairs from plywood and glass. The store has 30 units of plywood, 24 units of glass. Each table requires 7 units of plywood three units of glass, whereas each chair requires three units of plywood and two units of glass. The demand for chairs is between 2 and 4. The ratio between the table and chair is at least 1 to 2. A table earns $225 in profit and a chair, $145. The store also wants a minimum profit of $5000. The store wants to determine the number of tables and chairs to make in order to maximize profit. Formulate a linear programming model for this problem
4.Question 1: suppose the dealer has an an Ace showing, you have a 3 and an 8 in your hand,
r player at the table is showing a 5 and 6. Compute the expected value of a one-dollar insurance bet under these circumstances
Question 2: Suppose that( perhaps after being hit one or more times) you have cards addings up to 18. Using the table provided in these notes, compute the probability that you will lose, and the probability that you will tie.
Question 3: The "Royal Hand" consists of King and Queens of the same suit. Compute the probability of being dealt a Royal Hand in the first two cards.
Question 4: Compute the probability that you will initially be dealt two cards adding up to exactly 20. ( First think about how many ways two cards can up to 20 in blackjack.)
Question 5: You have two 9s in your hand. The dealer is showing a 7, and the only other player at the table is sowing a King and a 9. If you ask to be hit, what is the probability that you will bust on the next card?