A student is asked to standardize a solution of barium hydroxide. He weighs out 0.989 g potassium hydrogen phthalate (KHC8H4O4, treat this as a monoprotic acid). It requires 25.0 mL of barium hydroxide to reach the endpoint.
A. What is the molarity of the barium hydroxide solution?
This barium hydroxide solution is then used to titrate an unknown solution of hydroiodic acid.
B. If 18.0 mL of the barium hydroxide solution is required to neutralize 23.6 mL of hydroiodic acid, what is the molarity of the hydroiodic acid solution?
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A voltaic cell consists of Cu²⁺/Cu and Cd²⁺/Cd half-cells. Each compartment has a volume of 0.500 L with the following initial concentrations: [Cu²⁺] = 1.250 M; [Cd²⁺] = 0.250 M at 25°C. What is the [Cu²⁺] when the voltage has dropped to 0.719 V? (E⁰ for Cu²⁺/Cu = 0.340 V and E⁰ for Cd²⁺/Cd = -0.400 V.)
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Be sure to answer all parts. Calculate the volume in mL of a solution required to provide the following:
(a) 2.24 g of sodium chloride from a 0.415 M solution ___mL
(b) 5.40 g of ethanol from a 4.20 M solution ___mL
(c) 8.30 g of acetic acid (CH3COOH) from a 0.900 M solution ___mL
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Based on the calculated values of Kc for each reaction stoichiometry, which reaction is the valid one?
Fe(aq)3+ + SCN(aq)- FeSCN(aq)2+ The average value of Kc: 369.10
Fe(aq)3+ +2 SCN(aq)- Fe(SCN)2(aq)+ The average value of Kc: 988999.02
Briefly explain your conclusion. Compare the percent difference between the average value and the individual measurements. What does this tell you about the two possible stoichiometries? Do these reactions give consistent values of Kcfor different initial reaction conditions?
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how many grams of H2O can be produced when 45.5g of C3H8 reacts?
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Which of the following statements best describes a metabolic pathway?
1.the set of molecular reactions in which enzymes make or break down sugars
2.chemical reactions that do not involve the use of enzymes and that maintain homeostasis
3.a chemical reaction that makes or breaks down molecules
4.a linked sequence of chemical reactions catalyzed by specific enzymes
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A science teacher tells her class that their final project requires the students to measure a specific variable and determine the velocity of a car with no more than 2.5% error. Jennifer and Johnny work hard and decide the velocity of the car is 34.87 m/s. The teacher informs them that the actual velocity is 34.15 m/s. Will Jennifer and Johnny pass their final project? SHOW ALL YOUR WORK TO GET ANSWER.
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Polypropylene has a degree of crystallinity that is dependent on its tacticity. Why?
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A 1.000 g sample of copper reacts with an unknown element X to form 1.908 g Cu5X9. What is element X??
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Analyze how how efficiency can be just a function of the two temperatures for Carnot Cycle of ideal gas.
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In each of the following questions, assume that there is no volume change when HCl is added to water in part (a) or the phosphate buffer in part (c).
(a) Calculate the pH when 0.029 moles of HCl are added to 1.000 liter of water.
(b) What is the difference between the pH of pure water (pH 7.00) and the pH of the solution after HCl was added?
(c) Calculate the pH when 0.029 moles of HCl are added to 1.000 liters of a buffer containing 0.396 M KH2PO4 and 0.201 M K2HPO4.
(d) The pH before the HCl was added is equal to 6.913. What is the difference between the pH before adding the HCl and after adding the HCl?
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The reaction CH2Cl2 (g) --> CH4 (g) + CCl4 (g) has Kp = 1.33 at 400K. A 5.00L reaction vessel is evacuated, and 15.00 g of CH2Cl2 (l) is added to the flask. The CH2Cl2 (l) rapidly vaporizes and the reaction starts. a. What will be all of the partial pressures of the gases when equilibrium is reached? b. Sketch a graph showing the initial concentration of each gas and how they change as the mixture approaches equilibrium. Set-up your graph so that equilibrium is reacched two thirds of the way from the start to the end of the graph
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Some measurements of the initial rate of a certain reaction are given in the table below.
|
N2 |
H2 |
initial rate of reaction |
|---|---|---|
|
1.07M |
2.15M |
/17.0Ms |
|
1.07M |
0.951M |
/7.52Ms |
|
4.35M |
2.15M |
/281.Ms |
Use this information to write a rate law for this reaction, and calculate the value of the rate constant.
Round your value for the rate constant to 3 significant figures
Also be sure your answer has the correct unit symbol.
Rate = k?
k = ?
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