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# Physical Chemistry

### Indicator for a particular acid-base titration

Indicator for a particular acid-base titration. See attached file for full problem description.

### Balanced & Net Ionic Equations

Write the balanced molecular equation, complete ionic and net ionic equation for the following acid base reaction. HCL(aq) + NH3(aq) NH3 is an exception, so I'm not sure what to do with it.

### Combustion and Metal Reactions

14. The gaseous hydrocarbon acetylene, C2H2, is used in welders' torches because of the large amount of heat released when acetylene burns with oxygen, producing carbon dioxide and water. First, write a balanced equation for the combustion of acetylene in oxygen. Then, how many grams of acetylene are needed for the complete comb

### Salts and Their Reactions

7. When 1.00 grams of chromium metal is heated in excess iodine, 8.301 rams of chromium iodide salt is formed. Calculate the empirical formula of this salt. 8. When a calcium carbonate tablet is ingested, it dissolves by the reaction of stomach acid, which contains hydrochloric acid. The unbalanced equation for this reaction

### Find how many grams of oxygen

1. In the following problem, first find how many grams of oxygen would be used to completely react with 230 grams of pentyl alcohol (C5H11OH)? How many grams of oxygen would be used? See attached file for full problem description.

### Calculate the basic buffer capacity

Calculate the basic buffer capacity of a solution of 50.00 mL of 0.334 M HC2H3O2 to which is added 50.00 mL of 0.154 M NaC2H3O2.

### Percent manganese in a sample

A 0.500g sample is analyzed spectrophotometrically for manganese by dissolving it in acid and transferring to a 250mL flask and diluting to volume. Three aliquots are analyzed by transforming 50mL portions with a pipet to 500mL Erlenmeyer flasks and reacting with an oxidizing agent, potassium peroxydisulfate, to convert the mang

### Analysis of Calcite Sample

The analysis of a calcite sample yielded CaO percentages of 55.95, 56.00, 56.04, 56.08, and 56.23, respectively. The last value appears anomalous; should it be retained or rejected?

### PH, pOH, PKw Calculations

Calculating pH, POH, PKa, PKb. 59) Calculate the hydrogen ion concentration for a 0.0200 M solution of HCN in 0100 M NaCl.

### Chemistry: pH, pOH, pKW Sample Question

Calculating pH, POH, PKa, PKb. See the attached file.

### PH, pOH, PKw of a Prepared Solution

Calculating pH, POH, PKa, PKb. 43) Calculate the pH of a solution prepared by mixing 5.0 ml of 0.10 M NH3 with 10.0 ml of 0.020 M HCl.

### PH, pOH, PKw

Calculating pH, POH, PKa, PKb. 37) PH 0.600 M solution of Na2S Sodium sulfide is a salt of a weak acid (hydrogen sulfide) and a strong alkali (sodium hydroxide). It therefore undergoes hydrolysis in water. Na2S = 2Na+ + S2- S2- + 2H2O = H2S + 2OH- Kh = [H2S][OH-] [S2-] [OH-] = Kh[S2-] [H2S] PO

### PH, pOH, PKw

Calculating pH, POH, PKa, PKb.

### PH, pOH, PKw

Calculating pH, POH, PKa, PKb.

### PH, pOH, PKw

Calculating pH, pOH, pKw; Hydrolysis of salts of: weak acid and strong alkali or strong acid and weak alkali.

### Question about PH, pOH, PKw

Calculating pH, pOH, pKw; Hydrolysis of salts of: weak acid and strong alkali or strong acid and weak alkali.

### Analytical Chemistry Calculations

Calculation of pH, calculation of pOH, relationship between pH , pOh and pKw

### Analytical Chemistry Calculations Relationships

Calculation of pH, calculation of pOH, relationship between pH , pOh and pKw

### Chemical breakdown of toothpaste

A toothpaste contains 0.24% by mass of sodium fluoride used to prevent caries (cavities) and 0.30% by mass of triclosan (C12H7Cl3O2). A PRESERVATIVE + ANTIGINVITIS AGENT. a) How many moles of NaF are in a tube of toothpaste b) How many moles of F- are in a tube? c) How many grams of Na+ are in 1.50g of toothpaste? d) How man

### Purity of Zn(OH)2

The purity of a 0.287 -g samole of Zn(OH)2 is determined by titrating with a standard solution, requiring 37.8 mL. The HCL solution was standardized by precipitating AgCl in a 25.0-mL aliquot and weighing (0.462 g AgCl obtained). What is the purity of the Zn(OH)2 ?

### The thermochemical standard state of a substance is its most stable state under one atmosphere

16. Which of the following statements is incorrect? A.The thermo chemical standard state of a substance is its most stable state under one atmosphere pressure and at some specific temperature (298 K if not specified) B.A superscript zero, such as &#61508;H0, indicates a specified temperature of 0&#61616;C. C.For a pure sub

### What is the heat of combustion per gram of butane?

5. The combustion of butane produces heat according to the equation 2C4H10(g) + 13O2(g) &#61614; 8CO2(g) + 10H2O(l) &#61508;H° = -5,314 kJ What is the heat of combustion per gram of butane? A.-32.5 kJ/g B.-45.7 kJ/g C.-91.5 kJ/g D.-2,656 kJ/g E.-15,440 kJ/g 6. The freezing of water is an example of an exotherm

### In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon dioxide and water

See attached file for full problem description. 1. In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon dioxide and water: Calculate the value of q (kJ) in this exothermic reaction when 1.70 g of methane is combusted at constant pressure. A. -94.6 B. 0.0306 C. -0.0106 D.

### High-temperature equilibrium calculation

High-temperature equilibrium The data below are for the dissociation of PCl5 into PCl3 and Cl2, all in the gas phase. ? (a) What is ΔGo for the reaction at each of the five temperatures? ? (b) What is ΔHo for this reaction? ? (c) What is ΔSo for the reaction at each of the five temperatures? [Reference: A Textbook of

### Percentage of Cis Isomer at Equilibrium

Consider the trans-to-cis isomerization of 1,2-dichloroethylene. If the Gibbs energy of formation is 27.34 and 22.11 kJ / mol for the trans and cis isomers, respectively, what is the percent of cis isomer present at equilibrium? You may ignore activity corrections. See attached file for full problem description.

### Calorimetry, calculations of heat energy required etc.

7. It takes 585 J of energy to raise the temperature of 125.6 g mercury from 20.0 degrees C to 53.5 degrees C. Calculate the molar heat capacity of mercury in J/(mol degrees C). 8. The specific heat capacity of silver is 0.24 J/(g x degrees C). It takes 3.57 kJ of energy to heat a sample of pure silver from 12.0 degrees C

### Analytical Chemistry Questions: Ionic Strength

1. A and B react as follows: A + B = C + D. The equilibrium constant is 2.0 x 10^3. If 0.30 mol of A and 0.80 mol of B are mixed in 1 L, what are the concentrations fo A, B, C, and D after reaction? 4. The dissociation constant for hydrocyanic acid, HCN, is 7.2 x 10^-10. Calculate the percent dissociation of a 1.0 x 10^-3 M s

### Empirical Formula & Products

A compound of bromine and fluorine is used to make UF6, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37% by mass of bromine. Determine its empirical formula. A) BrF B) BrF2 C) Br2F3 D) Br3F E) BrF3 Magnesium reacts with iron(III) chloride to from magnesium chlo

### The standard potential for the reaction: Zn 2+ + 2e-

The standard potential for the reaction: Zn 2+ + 2e- = Zn is -0.763V. Based on this information, is Zn is a good or poor reducing agent? Explain.

### Indicator for Weak Base in Strong Acid

Suppose you are to titrate a weak base such as ammonia with a strong acid as HCl. What kind of indicator would you use and why?