Octane(C8H18) is a hydrocarbon found in crude oil. Thermochemical data for octane is provided below. The total change in enthalpy is 15.94 kJ when heating 0.2500 moles of octane from -70.00°C to 100.0°C. Determine the AHfusion. Melting point: -57.00 °C Boiling point: 126.0 °C J Csolid : 185.0 °C mol Ciquid: 254.0 J °C mol J C gas: 250.0 °C mol AHvap: 34.40 kJ/ mol Molar mass: 114.23 g/mol 0.2693 kJ/mol 4.720 kJ/mol 21.50 kJ/mol 0.2540 J/mol

7. An old "trick" for cooling down a hot beverage quickly is to immerse a cold spoon into the liquid. A silver spoon weighing 3.20 oz and at a temperature of 20°C is placed in a cup of hot coffee (8.00 oz) at 70°C. What will be the resulting liquid temperature? Assume that specific heat of coffee is 4.18 J g-1 °C-1 and that of silver is 0.234 J g-¹ °C-1. Comment on the effectiveness of this method of cooling a hot drink. 1 g = 0.0352 oz

4. An ice cube at a temperature of -4.0°C has a mass of 7.0 g. You add 150. mL of hot water (90.0°C) to the ice cube. The water cools to 50.00°C. Calculate the heat of fusion (Q) in kJ and the enthalpy of fusion (AH) in kJ/mol.

How much heat is rel;eased to the surroundings when 5.00 g of CO2 is produced according to the following thermochemical equation? C3H8 + 5 O2 --> 3 CO2 + 4 H, AHn = -2220 kJ/mol %3D Note: the molar mass of CO2 is 44.0 g/mol 757 kJ O252 kJ 740 kJ 84.1 kJ

Calculate the heat necessary to increase temperature of a) 100. g of water b) 2.00 mol H2O(l) from 20 ℃ to 100 ℃.

A calorimeter contains 100 g water. The calorimeter and the water inside are both at 21 °C. What mass of hot water 95 °C must be added to raise the temperature inside the calorimeter to 36 °C ? (Assume no heat leaks). calorimeter constant: 150 j°C1 specific heat of water: 4.184 J°c-1g-1 51.5 g Oa. Ob. 29.5 g O. 34.5 g O d. 42.5 g O e. 19.5 g A Moving to the next question prevents changes to this answer. Question 11 of 20 >

Using the following thermochemical data: 2Er(s) + 6HF(g) → 2ErF3(s) + 3H2(g) ΔH° = -1795.4 kJ/mol 2Er(s) + 6HCl(g) → 2ErCl3(s) + 3H2(g) ΔH° = -1443.6 kJ/mol calculate ΔH° for the following reaction:ErF3(s) + 3HCl(g) → ErCl3(s) + 3HF(g) 351.8 kJ/mol -3239.0 kJ/mol -1619.5 kJ/mol 703.6 kJ/mol 175.9 kJ/mol

Given the following thermochemical equation, what is the standard heat of formation for NaOH? 2NaOH(s)-->2Na (s) + O2 (g) + H2 (g) TriangeH= +875.6 kJ a) 875.6 kJ b) -875.6 kJ c) 437.6 kJ d) -437.6 kJ e) 1751.1 kJ f) -1751.1 kJ

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Constant is 4.184