question archive 1) How many J and cal are needed to heat 250 mg of diamond from -20 oC to 150 oC? 3
1) How many J and cal are needed to heat 250 mg of diamond from -20 oC to 150 oC? 3
Subject:ChemistryPrice: Bought3
1) How many J and cal are needed to heat 250 mg of diamond from -20 oC to 150 oC? 3. How many cal are needed to bring 1750 g ice from -20.0 oC to steam at 110 oC? 4. How many cal and J are needed to heat 34.6 g Freon 11 (CCl3F) from a liquid at -11.5oC to vapor at 50oC?Note, the melting point for CCl3F is -111 oC and the boiling point is +23.8 oC. 5. How many cal are needed to melt 125 g ice at 0 oC? 6. Calculate the energy needed to heat 25 g water from 65 oC to steam at 145 oC. 7. How many calories are needed to heat 87 g aluminum from solid at 500 oC to liquid at its melting point of 660 OC? 8. Calculate the specific heat of silicon metal if a 13.68 g sample at 100.00 oC is placed into 124.6 g water at 22.10 oC and warms the water to 23.51 oC. 9. A 25.0g sample of aluminum, taken from boiling water is placed into 85.00 g of water at 23.5 oC. Calculate the final temperature of the water. 10. Given the heat of fusion for water at the top of the page, convert it to a) J/g b) kJ/mole and c) kcal/mole. 11. How many grams of iron are in a sample if 25,000 cal are used to heat it from -15.6 oC to 250.4 oC? 12. What is the final temperature of a 250 g water solution if its initial temperature is 2.8oC and it is heated by 16,235 cal. 13. How many joules are needed to heat 25.0 g of water from 5.5 0C to steam at 122 oC? 14. How many joules are needed to heat 1.50 moles of water from 19.4 oC to 55.2 oC? 15. If 0.25 g acetylene (C2H2) are used to heat 100.0 g water at 22.0 oC to 37.0 oC, a) calculate the energy used. b) calculate the enthalpy of the reaction; in other words, find the numerical value for the energy in Reaction 1. Reaction 1: 2 C2H2 + 5 O2 → 4 CO2 + 2 H2O + Energy 16. The heat of solution for LiOH is -5.632 kcal/mole. Calculate the final temperature of a 100.0 g sample of water at 15.5 oC if 11.6 g LiOH is added. Assume the resulting solution has the same specific heat as pure water. 17. Calculate the enthalpy (ΔH)for the following reaction. Note Reaction is not balanced. CH3OH (l) + O2 (g) → CO2 (g) + H2O (L) 18. Calculate the molar heat of neutralization, in kJ and kcal, for 1 mole of sulfuric acid. When 50.0 mL of a 1.00 M sulfuric acid solution is mixed with 250. mL of a 0.400 M sodium hydroxide solution, the solution's temperature rises from 16.5 oC to 21.0 oC. 19. Using the reactions in Table 1, and Hess's law to calculate the energy, in kJ/mole needed to accomplish the following reaction. H2O (l) → H2O (g) 20. Plaster of Paris, CaSO4? ½ H2O, can be combined with water to form gypsum, CaSO4?2 H2O used in making plaster casts to prevent broken bones from moving while they heal. Calculate the energy for this reaction using the thermochemical data table, Table 2. CaSO4? 1/2 H2O(s) + 1 ½ H2O (L) → CaSO4?2 H2O (s)
