Solutions Questions and Answers

A certain substance X melts at a temperature of 3.6 °C. But if a 550. g sample of X is prepared with 27.9 g of urea ((NH2)2CO) dissolved in it, the sample is found to have a melting point of -1.6 °C instead. Calculate the molal freezing point depression constant Kf of X. Round your answer to 2 significant digits.

At a certain temperature the vapor pressure of pure acetone ((CH3)2CO) is measured to be 0.74 atm. Suppose a solution is prepared by mixing 79.4 g of acetone and 91.6 g of acetic acid (HCH3CO2). Calculate the partial pressure of acetone vapor above this solution. Round your answer to 2 significant digits.

At 25.0 °C the Henry's Law constant for phosphine (PH3) gas in water is 8.1 × 10^-3 M/atm. Calculate the mass in grams of PH3, gas that can be dissolved in 400. mL of water at 25.0 °C and a PH, partial pressure of 4.11 atm. Round your answer to 2 significant digits.

A student dissolves 12. g of benzoic acid (C,H,O₂) in 300. mL of a solvent with a density of 1.0 g/ml.. The student notices that the volume of the solvent does not change when the benzoic acid dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to 2 significant digits.

At 25.0 °C the Henry's Law constant for sulfur hexafluoride (SF6) gas in water is 2.4 x 10^-4 M/atm. Calculate the mass in grams of SF6, gas that can be dissolved in 550. mL of water at 25.0 °C and a SF6, partial pressure of 3.62 atm. Round your answer to 2 significant digits.

A student dissolves 4.1 g of methanol (CH3OH) in 350. mL of a solvent with a density of 0.83 g/mL. The student notices that the volume of the solvent does not change when the methanol dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to 2 significant digits.

At a certain temperature the vapor pressure of pure benzene (C6H6) is measured to be 312. mmHg. Suppose a solution is prepared by mixing 74.6 g of benzene and 57.3 g of acetyl bromide (CH3COBr). Calculate the partial pressure of benzene vapor above this solution. Round your answer to 3 significant digits. Note for advanced students: you may assume the solution is ideal.

2-6. A student pours 50 mL of water as carefully as possible into a 250 mL beaker. The water in the 250 mL is then poured into a graduated cylinder and the volume is read. The experiment was performed 3 times. For these three 3 runs, the amount of water in the graduated cylinder was 52.8 mL, 46.2 mL and 54.7 mL respectively. Calculate the percent accuracy of the results and the percent precision of the results. Do not use a spread sheet or automatic function in a calculator for this problem.

A student dissolves 9.5 g of styrene (C8H8) in 150. mL of a solvent with a density of 1.08 g/ml. The student notices that the volume of the solvent does not change when the styrene dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to 2 significant digits.

A student dissolves 19. g of phenol (C6H5OH) in 300. mL of a solvent with a density of 0.84 g/mL. The student notices that the volume of the solvent does not change when the phenol dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to 2 significant digits.

A chemist prepares a solution of sodium carbonate (Na2CO3) by weighing out 46.66 g of sodium carbonate into a 350. ml. volumetric flask and filling the flask to the mark with water. Calculate the concentration in g/dL of the chemist's sodium carbonate solution. Round your answer to 3 significant digits.

A chemist adds 225.0 mL of a 4.18 g/dL. potassium dichromate (K2Cr2O7) solution to a flask. Calculate the mass in grams of potassium dichromate the chemist has added to the flask. Round your answer to 3 significant digits.

A solution is made by mixing 39. g of heptane (C7H16) and 58. g of acetyl bromide (CH3COBr). Calculate the mole fraction of heptane in this solution. Round your answer to 2 significant digits.

Select all the options that correctly describe density. Check all that apply. When comparing equal masses of two different substances, the substance with the greater volume has the greater density. The density of a substance changes with changing temperature. The density of a substance depends on the amount of substance that is present. The density of an object is the ratio of its mass to its volume.

Identify the tone of the following sentence. I would appreciate it if you would provide me a reference letter. Casual Courteous Rude

You want to make (2.200x10^-1) L of a (8.0x10^-1) M copper (II) chloride solution. How many grams of copper (II) chloride are needed to make this solution? Answer in scientific notation with the correct number of significant figures. Note: 10^n is the same as 10⁰ Note: Your answer is assumed to be reduced to the highest power possible. Your Answer: Answer x10 units

A 8.17 g sample of an unknown salt (MM = 116.82 g/mol) is dissolved in 150.00 g water in a coffee cup calorimeter. Before placing the sample in the water, the temperature of the salt and water is 23.72°C. After the salt has completely dissolved, the temperature of the solution is 28.54°C. What is the total mass inside the calorimeter in grams?

Given the solubility of Ag2CO3(s) is 4.7 x 10-5 M, calculate the value of Ksp at 25 °C Ag2CO3(s) →2 Ag+ (aq) + CO3²- (aq) a) 4.2 x 10-13 Ob) 9.4 x 10-5 Oc) 1.0 x 10-13 d) 2.4 x 10-16

All of the following are added to five different containers of water, each with the same mass of water. Which resulting solution would yield the lowest freezing point? 1.0 mol of KBr 2.0 mol of RbSO4 3.0 mol of NaNO3 0.5 mol of C5H1005 2.0 mol of FeCl3 4.0 mol of CF4

A 4.305-g sample of a nonelectrolyte is dissolved in 105 g of water. The solution freezes at -1.23C. Calculate the molar mass of the solute. Kf for water = 1.86C/m. 46.2 g/mol 39.7 g/mol 58.4g/mol 62.0g/mol

A chemist prepares a solution of aluminum sulfate flask to the mark with water. Calculate the concentration in mol/L of the chemist's aluminum sulfate solution. Round your answer to 3 significant digits. mol/L x10 (Al₂(SO4)3) by measuring out 137. g of aluminum sulfate into a 250. mL. volumetric flask and filling the

Calculate the volume in milliliters of a 6.69M silver nitrate solution that contains 200. mmol of silver nitrate (AgNO3). Round your answer to 3 significant digits.

What mass of silver acetate is required to generate 25.0 grams of silver chromate? The molar mass of Ag2CrO4 is 331.74 g/mol. 2AgC₂H3O2 + K₂ CrO4 →Ag2 CrO4(s) + 2KC₂H302

The following is an acid-base reaction between sulfuric acid and aluminum hydroxide. Use the provided molar masses to answer the questions below: molar sulphuric acid mass 3 H₂SO4 g/mol 98.08 + aluminum hydroxide 2 Al(OH)3 78.00 aluminum sulfate Al2(SO4)3 342.15 Question no. D (6 pts) 18.0 ml of 1.28 M NaOH is diluted to a total volume of 3.00 L. Calculate the concentration of the final solution. + water 6 H₂O 18.02

A chemist prepares a solution of silver(1) perchlorate (AgClO4) by measuring out 79. µmol of silver(1) perchlorate into a 300. mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in mmol/L of the chemist's silver(I) perchlorate solution. Be sure your answer has the correct number of significant digits.

Calculate the mass percent of the following solution: 4.2g of LiBr in 52.6g of water

Determine the approximate volume (in mL) of a 0.120 M solution that contains 10.0 g of copper(II) sulfate, CuSO4. 790 mL 240 mL 83 mL 430 mL 520 mL 310 mL Not enough information to answer

Determine the molarity of each of the following solutions from its osmotic pressure at 25°C. Include the van't Hoff factor for the solutions when the factor is given. Report your answer to 3 sig figs as a decimal or in scientific notation e.g 2.45E-3 (it has to be a capital 'E') a. π=0.506 atm for a solution of ethanol b. π= 0.0239 atm for a solution of aspirin c. π=0.589 atm for a solution of CaCl2, i =2.47

Which of the following are colligative properties? Select all that apply. boiling point elevation vapor pressure elevation freezing point depression decrease in solubility freezing point elevation boiling point depression increase in solubility vapor pressure depression

Order the following compounds in terms of their vapor pressure from lowest to highest. CH3CH2CH3 CH3CH2OH CH3OCH3 CH3OCH3 < CH3CH2CH3 < CH3CH2OH CH3CH2CH3 < CH3CH2OH < CH3OCH3 CH3CH2OH < CH3OCH3 < CH3CH2CH3 CH3CH2OH < CH3CH2CH3 < CH3OCH3 CH3CH2CH3 < CH3OCH3 < CH3CH2OH

Calculate the percentage composition for NF3. Mass percentage of nitrogen = Mass percentage of fluorine =

Eye drops must be at the same osmotic pressure as the human eye to prevent water from moving into or out of the eye. A commercial eye drop solution is 0.327 M in electrolyte particles. What is the osmotic pressure (atm) in the human eye at 25 °C? Hint: = MRT; T = 25 °C + 273.15

If a certain mass of an ionic solute is added to a solvent such as water, which of the following freezing points is reasonable for the solution? Assume standard pressure. 124°C O 45°C O-17°C O 13°C

Ksp of a substance MX2 is 4 x 10-12 at temperature T. If molar mass of substance is 100 g/mol, then its solubility (in g/L) at temperature T is x, then the value of 100 x is

Radioactive tracers provide a convenient mean of measuring the small concentration encountered in determining ksp values. Exactly 30 ml of 0.001M AgNO3 solution containing radioactive silver, with an activity of 40000 counts per ml was mixed with 10 ml of 0.002 M KIOS solution and the mixture is diluted to exactly 400 ml. After equilibrium was reached, a portion of sample was filtered to remove any solid and was found to have an activity of 2000 counts per ml. The ksp of AgIO3 is - 6x 10-10 1.25 x 10-9 6x 10-12 4 × 10-10

N₂ + 3 H₂ → 2 NH3 If 7.00 moles of nitrogen react, how many liters of ammonia gas will be produced at STP? Round your answer to the nearest whole number.

What is the theoretical yield in grams of Ca(OH)2 if 2.04 g of KOH react with 3.02 g of CaCl2.2H2O as shown by the below equation? CaCl₂(aq) + 2KOH(aq) → Ca(OH)2(s) + 2KCl(aq) In the part of the calculation that converts the number of grams to moles for CaCl2.2H₂O, the two water molecules must be included in the molar mass needed to convert grams to moles (molar mass of CaCl₂.2H₂O is 147.0 g/mol).

A chemist must prepare 0.825 L of 2.00 M aqueous zinc nitrate (Zn(NO3)₂) working solution. He'll do this by pouring out some 2.65 mol/L aqueous zinc nitrate stock solution into a graduated cylinder and diluting it with distilled water. Calculate the volume in L of the zinc nitrate stock solution that the chemist should pour out. Be sure your answer has the correct number of significant digits.

27.9 g of a solute raises the boiling point of benzene to 83.74 °C. The mass of the benzene solvent is 367 g and the solute is nonionic. Find the molecular weight of the solute. Normal boiling point for benzene: 80.1°C; Kb = 2.53°C/m

Consider the following solutes. Which would have the greatest impact on freezing point depression? Be sure to choose the option that best explains your choice. KNO3 because it has a van't Hoff factor of 3. CaCl₂ because it has a van't Hoff factor of 3. Glucose (C6H1206) because it has a van't Hoff factor of 24. KNO3 because it has a van't Hoff factor of 5. Glucose (C6H1206) because it has a van't Hoff factor of 1. CaCl₂ because it will not ionize.

A student makes a solution for analysis by mixing 5.51 grams of Cu₂SO4 into 364.8 grams of water. The density of water at the temperature of the lab at the time the solution was made is 0.9926 g/mL. Calculate the molarity, molality, mole fraction, and mass percent of the copper I sulfate.

x-gram of NaNO₂ is dissolved in water to make 100 mL solution, 10 mL of this solution required 10 mL, 1.12 volume H₂O₂ for complete oxidation to make NaNO, in acidic medium. Find x (molar mass of NaNO₂ = 69 g/mol).

What is the osmotic pressure of a 1.4 M aqueous solution of glycerin in water at 47 °C? Report your answer in atm and round to the second decimal place. Glycerin = C3H5(OH)3

Calculate the molecular diameter, d, of the new at 325 K if they are known in the same conditions: a) The viscosity coefficient, n = 3.05 10-5 Pa s, or b) The thermal coefficient conductivity, k = 0.02385 W m-1 K-1

Which one of the following relationship is correct for one mole CO₂ gas in adiabatic expansion (do not consider vibrational degree of freedom)? pv1.4 = constant PV1.5 = constant TV0.3= constant p1.4 T0.4 = constant

A saline solution is administered intravenously to patients who cannot take fluid orally and are in danger of dehydration. The osmotic pressure of this solution must match that of blood to prevent hemolysis or crenation of blood cells. If the osmotic pressure of 100.0 mL saline solution is 7.83 atm at a body temperature of 37.0°C? (R= 0.08206 L atm/mole K or 62.4 L torr/mole K) Partl: What would be the Molarity of the above saline solution ? 0.308 M Part II: What mass of sodium chloride (58.44 g/mol) is needed to produce the above saline solution? 1.80 g

Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natural gas. In the first step, nitrogen and hydrogen react to form ammonia: N₂(g) + 3 H₂(g) → 2 NH3(g) ΔH=-92. kJ In the second step, ammonia and oxygen react to form nitric acid and water: NH3(g) + 2O₂(g) → HNO3(g) + H₂O(g) ΔH=-330. kJ Calculate the net change in enthalpy for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen from these reactions. Round your answer to the nearest kJ.

Which type of reaction is occurring during a fireworks show? How do you know? It is an exothermic reaction. Heat must be added to light the fuses of the fireworks. It is an exothermic reaction. Fireworks are bright, indicating a release of light energy. It is an endothermic reaction. Fireworks are bright, indicating a release of light energy. It is an endothermic reaction. Heat must be added to light the fuses of the fireworks.

During electrolysis of aqueous conctrated NaCl using Pt-electrodes, if 3 moles of water is electrolyted then how much charge (in Faradays) is required if current effeciency is 75%

Osmotic pressure of urea solution is 500 mm of Hg at 10°C. The solution is diluted and the temperature is raised to 25°C, when osmotic pressure is found to be 105.3 mm of Hg. The extent of dilution is times.