Homework Answers
The properties that are essential for the salt in an effective cold pack are:
dissolves quickly (for immediate reaction)
dissolving in water is an endothermic reaction (heat is absorbed from the surroundings and therefore the temperature is lowered)
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QUESTION 2 What properties are essential for the salt in an effective cold pack? dissolves only...
2. A cold pack consists of an inner pouch containing ammonium nitrate, NHĄNO (), and an...
2. A cold pack consists of an inner pouch containing ammonium nitrate, NHĄNO (), and an outer pouch of water. Twisting the pack breaks the inner pouch and allows the water and ammonium nitrate to mix. As the ammonium nitrate dissolves, the temperature of the surroundings decreases. The energy change per mole of ammonium nitrate dissociated is 25.7 kJ. (a) Classify the reaction as endothermic or exothermic. [ans: endothermic (b) Draw a potential energy diagram for the reaction. Label the...
T U IF I question. The salt potassium bromide dissolves in water according to the reaction:...
T U IF I question. The salt potassium bromide dissolves in water according to the reaction: KBr(s) + (aq) + Br"(aq) (a) Calculate the standard enthalpy change AH for this reaction, using the following data: AH?KBr(s) --393.8 kJ mol! AHK (aq) --252.4 kJ mol! AH Br"(aq) --121.6 kJ mol' (b) Calculate the temperature reached by the solution formed when 53.9 g of KBr is dissolved in 0.149 L of water at 22.9 °C. Approximate the heat capacity of the solution...
The salt ammonium chloride dissolves in water according to the reaction: NH_CI) —NH4+ (aq) + Cl(aq)...
The salt ammonium chloride dissolves in water according to the reaction: NH_CI) —NH4+ (aq) + Cl(aq) (a) Calculate the standard enthalpy change AH° for this reaction, using the following data: AH NHACI() = -314.4 kJ mol-1 AHNH4+(aq) = -132.5 kJ mol-1 AH; Cr(aq) = -167.2 kJ moll kJ (b) Calculate the temperature reached by the solution formed when 36.8 g of NH4Cl is dissolved in 0.186 L of water at 23.7 °C. Approximate the heat capacity of the solution by...
one of the test tubes will be put in the cold water bath(ice,on scoop of salt...
one of the test tubes will be put in the cold water bath(ice,on scoop of salt and water in a 250ml beaker)for five minutes.one of the test tubes will be put in a 60 degrees celcius warm water bath for 5 minutes.Put all three test tubes in 125 ml erlenmeyer flasks to stand them up,and compare the colors,below is the equillibrium equation that governs the reaction. Bases on this,determine if the reaction is exothermic or endothermic. [Co(H2O)6]2+ +4HCL------[CoCL4]2- + 6h20
Question 2: Rate of Dissolving (9 points) a.) A student wants to determine how long it...
Question 2: Rate of Dissolving (9 points) a.) A student wants to determine how long it takes to dissolve 51.3 g of common table salt (sodium chloride) in 1L of water by monitoring the solution. It takes 26.7 seconds for the salt to completely dissolve. Determine the rate of dissolution. (2 points) b.) Describe the rate constant expression if the reaction was first-order in NaCl. (2 points) c.) Write the equation that can be used to predict that change in...
want to check 4 5 and 6 (4) KNO; (s) can be dissolved in water. The...
want to check 4 5 and 6
(4) KNO; (s) can be dissolved in water. The dissolution causes the solution temperature decrease. What true about KNO3 (s)? (a) The dissolution is exothermic, and KNO3 (s) can be used as hot pack. (b) The dissolution is endothermic, and KNO3 (s) can be used as hot pack. (c) The dissolution is endothermic, and KNO3 (s) can be used as cold pack. (d) The dissolution is exothermic, and KNO3 (s) can be used...
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...
1. Instant cold packs used to ice athletic injuries on the field contain ammonium nitrate and...
1. Instant cold packs used to ice athletic injuries on the field contain ammonium nitrate and water separated by a thin plastic divider. When the divider is broken, the ammonium nitrate dissolves according to the following reaction: NH4NO3 (s) à NH4 (aq) + NO3- (aq) In order to measure the enthalpy change for this reaction, 1.25 g of NH4NO3 was dissolved in 25.0 g of water. The initial temperature was 25.8 ° C and the final temperature (after all solid...
Compound Δ Hrxn (kJ/mol) NH4NO3 + 25.7 KCl + 17.2 NaOH -44.5 KOH -57.6 You are...
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...
E) Mg?"(aq) + 2 NO, (aq) —> Mg(NO)>(s) 8. When solid ammonium nitrate (NH.NOs) dissolves in...
E) Mg?"(aq) + 2 NO, (aq) —> Mg(NO)>(s) 8. When solid ammonium nitrate (NH.NOs) dissolves in water, the process is endothermic, with AH solution = +25.69 kJ/mol. (This reaction has been used in commercial cold packs.) If 5,60 8 NH.NO, is dissolved in 100.0 g of water at 22.0° C, what is the final temperature of the solution? The mass of the solution is 105.6 g (100.0 8 +5,60 g = 105.68) and its specific heat capacity is 4.18 J/(8-K)....
2. A cold pack consists of an inner pouch containing ammonium nitrate, NHĄNO (), and an outer pouch of water. Twisting the pack breaks the inner pouch and allows the water and ammonium nitrate to mix. As the ammonium nitrate dissolves, the temperature of the surroundings decreases. The energy change per mole of ammonium nitrate dissociated is 25.7 kJ. (a) Classify the reaction as endothermic or exothermic. [ans: endothermic (b) Draw a potential energy diagram for the reaction. Label the...
T U IF I question. The salt potassium bromide dissolves in water according to the reaction: KBr(s) + (aq) + Br"(aq) (a) Calculate the standard enthalpy change AH for this reaction, using the following data: AH?KBr(s) --393.8 kJ mol! AHK (aq) --252.4 kJ mol! AH Br"(aq) --121.6 kJ mol' (b) Calculate the temperature reached by the solution formed when 53.9 g of KBr is dissolved in 0.149 L of water at 22.9 °C. Approximate the heat capacity of the solution...
The salt ammonium chloride dissolves in water according to the reaction: NH_CI) —NH4+ (aq) + Cl(aq) (a) Calculate the standard enthalpy change AH° for this reaction, using the following data: AH NHACI() = -314.4 kJ mol-1 AHNH4+(aq) = -132.5 kJ mol-1 AH; Cr(aq) = -167.2 kJ moll kJ (b) Calculate the temperature reached by the solution formed when 36.8 g of NH4Cl is dissolved in 0.186 L of water at 23.7 °C. Approximate the heat capacity of the solution by...
want to check 4 5 and 6
(4) KNO; (s) can be dissolved in water. The dissolution causes the solution temperature decrease. What true about KNO3 (s)? (a) The dissolution is exothermic, and KNO3 (s) can be used as hot pack. (b) The dissolution is endothermic, and KNO3 (s) can be used as hot pack. (c) The dissolution is endothermic, and KNO3 (s) can be used as cold pack. (d) The dissolution is exothermic, and KNO3 (s) can be used...
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...
E) Mg?"(aq) + 2 NO, (aq) —> Mg(NO)>(s) 8. When solid ammonium nitrate (NH.NOs) dissolves in water, the process is endothermic, with AH solution = +25.69 kJ/mol. (This reaction has been used in commercial cold packs.) If 5,60 8 NH.NO, is dissolved in 100.0 g of water at 22.0° C, what is the final temperature of the solution? The mass of the solution is 105.6 g (100.0 8 +5,60 g = 105.68) and its specific heat capacity is 4.18 J/(8-K)....
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