반응형 일반화학/[05장] 열화학384 C6H5COOH -3226.7 kJ/mol 1.9862 g 21.84℃ 25.67℃ C6H5COOH -3226.7 kJ/mol 1.9862 g 21.84℃ 25.67℃ The enthalpy of combustion of benzoic acid (C6H5COOH) is commonly used as the standard for calibrating constant-volume bomb calorimeters; its value has been accurately determined to be –3226.7 kJ/mol. When 1.9862 g benzoic acid are burned in a calorimeter, the temperature rises from 21.84℃ to 25.67℃. What is the heat capacity of the bomb? (A.. 2024. 4. 24. C6H12O6 4.117 g 19.65 kJ/℃ 3.134℃ mass percent C6H12O6 4.117 g 19.65 kJ/℃ 3.134℃ mass percentcalculate the percent by mass of the glucose in the sample A 4.117 g impure sample of glucose (C6H12O6) was burned in a constant-volume calorimeter having a heat capacity of 19.65 kJ/℃. If the rise in temperature is 3.134℃, calculate the percent by mass of the glucose in the sample. Assume that the impurities are unaffected by the combustion.. 2024. 4. 24. 50.0 g metal 100.0℃ 24.8℃ 50.0 g water 51.2℃ 50.0 g metal 100.0℃ 24.8℃ 50.0 g water 51.2℃ Suppose 50.0 g of water in the Styrofoam cup has an in initial temperature of 24.8℃. When a 50.0 g piece of metal at a temperature of 100.0℃ is added, the temperature of the water and metal rise to final temperature of 51.2℃. What is the specific heat of this metal object? (Specific heat of water is 4.184 J/g•℃) 열용량과 비열 q = C m Δt ( 참고 https://ywpop.t.. 2024. 4. 20. 2H2O2(l) ΔH = -196 kJ H2O2(l) 5.00 g 2H2O2(l) ΔH = -196 kJ H2O2(l) 5.00 g Hydrogen peroxide can decompose to water and oxygen by the reaction: 2H2O2(l) → 2H2O(l) + O2(g) ... ΔH = –196 kJ Calculate the quantity of heat released when 5.00 g of H2O2(l) decomposes at constant pressure. 2H2O2(l) → 2H2O(l) + O2(g) ... ΔH = –196 kJ 2몰 H2O2의 분해열이 –196 kJ 이므로, ΔH = –196 kJ / 2 mol = –98 kJ/mol ---> H2O2 1몰당 분해열 H2O2의 몰질량 = 34.01 g/mol 이므로, .. 2024. 4. 20. 75 kg 165 lb 555 ft Washington monument work kJ 25% energy 75 kg 165 lb 555 ft Washington monument work kJ 25% energy How much work is done when a person weighing 75 kg (165 lb) climbs the Washington monument. 555 ft high? How many kilojoules must be supplied to do this muscular work, assuming that 25% of the energy produced by the oxidation of food in the body can be converted into muscular mechanical work. 1 ft = 0.3048 m 이므로, ( 참고 https://ywpop.tisto.. 2024. 3. 30. mass 284 g 25.3℃ Ag 1.13 kJ heat absorb final temp mass 284 g 25.3℃ Ag 1.13 kJ heat absorb final temp 질량이 284 g이고 온도가 25.3℃인 은 덩어리가 1.13 kJ의 열을 흡수하였다. 은의 최종 온도는 얼마인가? 단, 은의 비열은 0.235 J/g•℃ A 284 g sample of silver (C = 0.235 J/g•℃) initially at 25.3℃ was heated with 1.13 kJ of heat. What was the final temperature of the silver? q = C m Δt ( 참고 https://ywpop.tistory.com/2897 ) Δt = q / C m = (1130 J) / [(0.235 J/g•℃) (284 g)] = (1130) / [(0.235) .. 2024. 3. 24. 비열 1, 질량 2 kg, 초기온도 80℃ 비열 1, 질량 2 kg, 초기온도 80℃ 비열 1, 질량 2 kg, 초기온도 80℃인 a와 비열 0.2, 질량 5 kg, 초기온도 10℃인 b를 혼합했을 때 최종온도는? [참고] 열용량과 비열 [ https://ywpop.tistory.com/2897 ] q = C m Δt 고온 물질이 잃은 열(–q) = 저온 물질이 얻은 열(+q) 최종온도 = x 라 두면, –[(1) (2) (x – 80)] = +[(0.2) (5) (x – 10)] –2x + 160 = x – 10 3x = 170 x = 170 / 3 = 56.67 답: 약 57℃ [키워드] 고온 물질이 잃은 열 기준 2024. 3. 17. 1.00 M AgNO3 20.0 mL 1.00 M KBr 20.0 mL AgBr 25.0℃ 35.0℃ 1.00 M AgNO3 20.0 mL 1.00 M KBr 20.0 mL AgBr 25.0℃ 35.0℃ 1.00 M AgNO3 20.0 mL와 1.00 M KBr 20.0 mL를 섞으면 AgBr 침전이 생기면서 온도가 25.0℃에서 35.0℃로 변한다. 이 침전 반응의 반응 엔탈피(kJ/mol)는? 단, 혼합 수용액의 밀도 = 1.00 g/mL, 비열은 4.2 J/g•℃이다. 혼합 수용액의 질량 = (20.0 + 20.0 mL) (1.00 g/mL) = 40.0 g Δt = 35.0 – 25.0 = 10.0℃ q = C m Δt ( 참고 https://ywpop.tistory.com/2897 ) = (4.2) (40.0) (10.0) = 1680 J 반응한 AgNO3의 몰수를 계산하면, (1.00 mol/.. 2024. 2. 25. ΔH 계산. 2CH4(g) → C2H4(g) + 2H2(g) ΔH 계산. 2CH4(g) → C2H4(g) + 2H2(g) Determine the enthalpy of reaction for 2CH4(g) → C2H4(g) + 2H2(g) using the equations: 1) 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(l) ... ΔH° = –3120.8 kJ 2) CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) ... ΔH° = –890.3 kJ 3) C2H4(g) + H2(g) → C2H6(g) ... ΔH° = –136.3 kJ 4) H2(g) + 1/2 O2(g) → H2O(l) ... ΔH° = –285.8 kJ --------------------------------------------------- 답: ΔH°.. 2023. 12. 20. C2H5OH gasoline ΔH_f° = –277.63 kJ/mol 1 gallon C2H5OH gasoline ΔH_f° = –277.63 kJ/mol 1 gallon For ethanol, C2H5OH, which is mixed with gasoline to make the fuel gasohol, ΔH_f° = –277.63 kJ/mol. Calculate the number of kJ released when exactly 1 gallon(s) of ethanol is burned completely. The density of ethanol is 0.787 g cm^-3. 에탄올 1갤런이 완전히 연소하였을 때 방출되는 kJ의 양을 계산하시오. --------------------------------------------------- 답: –88384 kJ [Blogger 블.. 2023. 9. 26. 이전 1 2 3 4 ··· 39 다음 반응형