Homework Answers
1. endothermic because temperture drops
2. Heat released = mass of water * specific heat of water * temperature change = 250 * 4.184 * (21 - 17.1) = 4079.4 J = 4.08 KJ
3. Moles of KCl = mass / molar mass = 12.1 / 74.5 = 0.162 moles
Standard enthalpy of solution = Heat / moles = 4.08 / 0.162 = 25.19 KJ/mol
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A student dissolves 12.1 g of potassium chloride (KCl) in 250. g of water in a...
A student dissolves 10.3 g of sodium chloride (NaCl) in 250. g of water in a...
A student dissolves 10.3 g of sodium chloride (NaCl) in 250. g of water in a well-insulated open cup. She then observes the temperature of the water fall from 22.0°C to 21.5°C over the course of 4.4 minutes. Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction: NaCl(s) - Na (aq) + Cl" (aq) You can make any reasonable assumptions about the physical properties of the solution. Be...
A student dissolves 15.0 g of ammonium chloride (NH,CI) in 250. g of water in a...
A student dissolves 15.0 g of ammonium chloride (NH,CI) in 250. g of water in a well-insulated open cup. She then observes the temperature of the water fall from 20.0°C to 16.0 °C over the course of 5.3 minutes. Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction: NHCl(s) + NH(aq) + Cl (aq) You can make any reasonable assumptions about the physical properties of the solution. Be...
A student runs two experiments with a constant-volume "bomb" calorimeter containing 1200. g of water (see...
A student runs two experiments with a constant-volume "bomb" calorimeter containing 1200. g of water (see sketch at right). thermometer stirrer water First, a 8.000 g tablet of benzoic acid (C H CO,H is put into the "bomb" and burned completely in an excess of oxygen. (Benzoic acid is known to have a heat of combustion of 26.454 kJ/g.) The temperature of the water is observed to rise from 12.00 °C to 48.74 °C over a time of 11.3 minutes....
Chem 1 problem. Please answer all with steps. Thank you so much 2. When 26.6 g of potassium chloride dissolves in 300.0...
Chem 1 problem. Please answer all with steps. Thank you so
much
2. When 26.6 g of potassium chloride dissolves in 300.0 g of water, the temperature drops from 26.1°C to 11.7°C. The C of the calorimeter is 22.0 J/oC. cal (a) Write an equation for solid potassium chloride dissociating into ions when it dis- solves in water. (b) Is the reaction endothermic or exothermic? (c) What is the sign of AH? (d) What is the value of "q" for...
Incorrect Your answer is incorrect • Row 2: Your answer is wrong. In addition to checking...
Incorrect Your answer is incorrect • Row 2: Your answer is wrong. In addition to checking your math, check that you used the right data and DID NOT round any intermediate calculations • Row 3: Your answer is wrong. In addition to checking your moth, check that you used the right data and DID NOT round any intermediate calculations. thermometer stimer A student runs two experiments with a constant volume "bomb" calorimeter containing 1500 g of water (see sketch at...
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Compound Δ Hrxn (kJ/mol) NH4NO3 + 25.7 KCl + 17.2 NaOH -44.5 KOH -57.6 You are given 6.9 grams of an unknown salt. You dissolve it in 56.5 mL of water. As the salt dissolves, the temperature of the solution changes from an initial temperature of 28.9°C to a final temperature of 22.9°C. Based on the chart of ΔH values and the temperature change, you can determine which salt you have. What is the temperature change? Δ T = o C...
An aqueous potassium chloride, KCI, solution is made by dissolving 0,350 mol KCl in 6000 g...
An aqueous potassium chloride, KCI, solution is made by dissolving 0,350 mol KCl in 6000 g of water. Calculate the molality of the solution molality: Choose the best definition for the activated complex, or transition state, from the list below. O A material in the process of changing from solid to liquid or liquid to as A low energy, short-lived molecule that is made in an early step of the reaction and consumed in a later step. A transient, high...
10. When sodium chloride dissolves in water, the ions dissociate: NaCl (s) = Na+ (aq) +...
10. When sodium chloride
dissolves in water, the ions dissociate: NaCl (s) = Na+
(aq) + Cl- (aq)
Write ionic equations, similar to the one above, that describe
how NaNO3 and NaCH3CO2 each
dissociate as they dissolve in water. Include heat as a reactant or
product in each equation.
Here is what I answered:
NaNO3 (s) = Na+ +
NO3- + heat
NaC2H3O2 + Heat =
Na+ +
C2H3O2-(ag)
Lab data table attached to determine where to place heat.
AGO no...
12:47 1 Exit Question 1 0.5 pts When 34.8 g of sodium chloride is dissolved in...
12:47 1 Exit Question 1 0.5 pts When 34.8 g of sodium chloride is dissolved in water, 2.31 kJ of energy is absorbed. Is the enthalpy of dissolution of NaCl exothermic or endothermic? Endothermic Exothermic Question 2 0.5 pts What is the balanced thermochemical equation for the combustion of two moles of gaseous acetylene, C2H2, with oxygen to produce carbon dioxide and water vapor at 24.59°C given that 2512 kJ of heat is released at a constant pressure of 1.14...
Bonus Chapter 6 Question Page 176.12412 A student had five coffee cup calorimeters, each containing 60.0....
Bonus Chapter 6 Question Page 176.12412 A student had five coffee cup calorimeters, each containing 60.0. mL of 0.833 M NaOH(aq) and all at room temperature (25.0°C) and pressure (1.00 atm). The student planned to add a weighed quantity of solid diprotic L-ascorbic acid, C.HO, to each beaker, stir, and measure the increase in temperature. The student ran out of time and was unable to complete the experiment. Her data is as follows: Experiment Mass of Ascorbic Acid, g 2.20...
A student dissolves 10.3 g of sodium chloride (NaCl) in 250. g of water in a well-insulated open cup. She then observes the temperature of the water fall from 22.0°C to 21.5°C over the course of 4.4 minutes. Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction: NaCl(s) - Na (aq) + Cl" (aq) You can make any reasonable assumptions about the physical properties of the solution. Be...
A student dissolves 15.0 g of ammonium chloride (NH,CI) in 250. g of water in a well-insulated open cup. She then observes the temperature of the water fall from 20.0°C to 16.0 °C over the course of 5.3 minutes. Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction: NHCl(s) + NH(aq) + Cl (aq) You can make any reasonable assumptions about the physical properties of the solution. Be...
A student runs two experiments with a constant-volume "bomb" calorimeter containing 1200. g of water (see sketch at right). thermometer stirrer water First, a 8.000 g tablet of benzoic acid (C H CO,H is put into the "bomb" and burned completely in an excess of oxygen. (Benzoic acid is known to have a heat of combustion of 26.454 kJ/g.) The temperature of the water is observed to rise from 12.00 °C to 48.74 °C over a time of 11.3 minutes....
Chem 1 problem. Please answer all with steps. Thank you so
much
2. When 26.6 g of potassium chloride dissolves in 300.0 g of water, the temperature drops from 26.1°C to 11.7°C. The C of the calorimeter is 22.0 J/oC. cal (a) Write an equation for solid potassium chloride dissociating into ions when it dis- solves in water. (b) Is the reaction endothermic or exothermic? (c) What is the sign of AH? (d) What is the value of "q" for...
Incorrect Your answer is incorrect • Row 2: Your answer is wrong. In addition to checking your math, check that you used the right data and DID NOT round any intermediate calculations • Row 3: Your answer is wrong. In addition to checking your moth, check that you used the right data and DID NOT round any intermediate calculations. thermometer stimer A student runs two experiments with a constant volume "bomb" calorimeter containing 1500 g of water (see sketch at...
An aqueous potassium chloride, KCI, solution is made by dissolving 0,350 mol KCl in 6000 g of water. Calculate the molality of the solution molality: Choose the best definition for the activated complex, or transition state, from the list below. O A material in the process of changing from solid to liquid or liquid to as A low energy, short-lived molecule that is made in an early step of the reaction and consumed in a later step. A transient, high...
10. When sodium chloride
dissolves in water, the ions dissociate: NaCl (s) = Na+
(aq) + Cl- (aq)
Write ionic equations, similar to the one above, that describe
how NaNO3 and NaCH3CO2 each
dissociate as they dissolve in water. Include heat as a reactant or
product in each equation.
Here is what I answered:
NaNO3 (s) = Na+ +
NO3- + heat
NaC2H3O2 + Heat =
Na+ +
C2H3O2-(ag)
Lab data table attached to determine where to place heat.
AGO no...
12:47 1 Exit Question 1 0.5 pts When 34.8 g of sodium chloride is dissolved in water, 2.31 kJ of energy is absorbed. Is the enthalpy of dissolution of NaCl exothermic or endothermic? Endothermic Exothermic Question 2 0.5 pts What is the balanced thermochemical equation for the combustion of two moles of gaseous acetylene, C2H2, with oxygen to produce carbon dioxide and water vapor at 24.59°C given that 2512 kJ of heat is released at a constant pressure of 1.14...
Bonus Chapter 6 Question Page 176.12412 A student had five coffee cup calorimeters, each containing 60.0. mL of 0.833 M NaOH(aq) and all at room temperature (25.0°C) and pressure (1.00 atm). The student planned to add a weighed quantity of solid diprotic L-ascorbic acid, C.HO, to each beaker, stir, and measure the increase in temperature. The student ran out of time and was unable to complete the experiment. Her data is as follows: Experiment Mass of Ascorbic Acid, g 2.20...
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