5. Calculate the enthalpy of the following reaction: 2Mg + 02 → 2MgO Given: Mg + 2HCI →>> MgCl2 + H2 AH = -21.0 kJ MgO + 2HCI → MgCl2 + H₂O AH = -33.5 kJ H₂+12 02 → H₂O AH = -76.0 kJ 6. A student is determining the enthalpy of solution for ammonium nitrate by adding ammonium nitrate to a calorimeter and measuring the temperature change. The accepted value is ΔΗ sol'n = 25.7 kJ/mol. A student, not paying attention, adds 1.5g of ammonium nitrate instead of 1.0g. When they perform their calculations, they use 1.0g as the mass. Will their calculation result in an answer that is higher than the accepted value or lower? Explain. 2. When 25.0 mL of 0.25 mol/L LiOH and 25.0 mL of 0.25 mol/L HCI are mixed together, the temperature warms 15.8°C. What is the molar enthalpy of neutralization for LiOH? 3. Instant hot packs work by crystallizing sodium acetate (NaCH3COO). The molar enthalpy of crystallization for sodium acetate is -56.7 kJ/mol. How many grams of sodium acetate are needed to warm 125.0 mL of water from 21.0°C to 35.4°C? 4. If 3.65g of butane is burned underneath a cup holding 1.00 L of water at 21.0°C, what will the final temperature of the water be (AH =-3325 kJ/mol)? comb

5. Calculate the enthalpy of the following reaction: 2Mg + 02 → 2MgO Given: Mg + 2HCI →>> MgCl2 + H2 AH = -21.0 kJ MgO + 2HCI → MgCl2 + H₂O AH = -33.5 kJ H₂+12 02 → H₂O AH = -76.0 kJ 6. A student is determining the enthalpy of solution for ammonium nitrate by adding ammonium nitrate to a calorimeter and measuring the temperature change. The accepted value is ΔΗ sol'n = 25.7 kJ/mol. A student, not paying attention, adds 1.5g of ammonium nitrate instead of 1.0g. When they perform their calculations, they use 1.0g as the mass. Will their calculation result in an answer that is higher than the accepted value or lower? Explain. 2. When 25.0 mL of 0.25 mol/L LiOH and 25.0 mL of 0.25 mol/L HCI are mixed together, the temperature warms 15.8°C. What is the molar enthalpy of neutralization for LiOH? 3. Instant hot packs work by crystallizing sodium acetate (NaCH3COO). The molar enthalpy of crystallization for sodium acetate is -56.7 kJ/mol. How many grams of sodium acetate are needed to warm 125.0 mL of water from 21.0°C to 35.4°C? 4. If 3.65g of butane is burned underneath a cup holding 1.00 L of water at 21.0°C, what will the final temperature of the water be (AH =-3325 kJ/mol)? comb

Chemistry & Chemical Reactivity

10th Edition

ISBN:9781337399074

Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel

Publisher:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel

Chapter20: Environmental Chemistry-earth's Environment, Energy, And Sustainability

Section20.7: Green Chemistry And Sustainability

Problem 2.1ACP: Assume that a sample of hard water contains 50. mg/L of Mg2+ and 150 mg/L of Ca2+, with HCO3 as the...

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