A volume of 120. mL of H2O is initially at room temperature (22.0 °C). A chilled steel rod at 2.00 °C is placed in the water. If the final temperature of the system is 21.0 °C , what is the mass of the steel bar? Use the following values: specific heat of water = 4.18 J g1 °C-1 specific heat of steel = 0.452 J g¯1 °C1 Express your answer to three significant figures and include the appropriate units.

A chunk of platinum weighing 19.36 grams and originally at 98.22 °C is dropped into an insulated cup containing 77.94 grams of water at 21.09 °C. Thermometer Water Metal- sample Stirring rod The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.72 J/°C. Using the accepted value for the specific heat of platinum (See the References tool), calculate the final temperature of the water. Assume that no heat is lost to the surroundings. Tfinal = °℃

A total of 2.00 mol of a compound is allowed to react with water in a foam coffee cup and the reaction produces 156 g of solution. The reaction caused the temperature of the solution to rise from 21.00 to 24.70 degrees Celsius. What is the enthalpy of this reaction? Assume that no heat is lost to the surroundings or to the coffee cup itself and that the specific heat of the solution is the same as that of pure water. Enter your answer in kilojoules per mole of compound to three significant figures.

The flame in a torch used to cut metal is produced by burning acetylene (C2H2)(26.04 g/mol) in pure oxygen. Assuming the combustion of 1 mole of acetylene releases 1251 kJ of heat, what mass of acetylene is needed to cut through a piece of steel if the process requires 22.5  × 104 kJ of heat?                                            2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(g) ΔH = –2502 kJ