4A chemical reaction is run in 450 grams of liquid water, resulting in the water increasing from a temperature of 15 °C to 95 °C. a. Use the equations in your textbook to calculate how much heat is absorbed by the water? b. What is the change in enthalpy for the system? c. What is the change in enthalpy for the surroundings?

12. When freezing weather threatens the citrus crop in Florida, growers spray their orange trees with water, using their knowledge of enthalpy to protect the fruit. How much heat is released when 1000 g of liquid water at 10.0°C is completely converted to ice of a temperature of -2.0°C? A. 8.2 x 104 J B: 6.1 x 105 J C. 3.3 x 105 J D.) 3.8 x 10³ J E. 4.2 x 104 J

A sheet of metal weighing 275-g is heated to 100.0 °C and placed flat in 100.00 g bucket of water at 22.0 °C. What is the final temperature of the combined substances? Assume that no heat is lost to the surroundings. The specific heat capacity of the metal is 0.444 J/g.°C . The specific heat of water is 4.184 J/g.°C. Select one: O a. 61.0 °C Оъ. 82.4 °С O c. 79.2 °C d. 40.8 °C × О е. 39.6 °C

Propane is a gas commonly used to fuel gas grills and camping stoves.  The structure of propane is shown below. Write the balanced chemical equation for the combustion of propane.  Draw out lewis dot structures to represent all molecules of all products and reactants in this reaction.  The number of each molecule should be reflected in the balanced equation.  Calculate the heat of combustion for propane using the bond enthalpies in the table.  1.00 mol of propane is used to roast marshmallows.  It was determined that the amount of energy absorbed by the marshmallows was only 800 kJ.  Explain this observation.

The molar heat of solution of a substance is found to be +21.38 kJ/mol. The addition of 0.100 mol of this substance to 1.000L of water initially at 40.0 degrees celsius results in a temperature decrease. Assume the specific heat of the resulting solution to be equal to that of pure water. Find the final temperature of the solution (Also assume that the heat capacity of the calorimeter is negligible).

A 54.5 g sample of brass is put into a calorimeter (see sketch at right) that contains 300.0 g of water. The brass sample starts off at 95.8 °C and the temperature of the water starts off at 15.0 °C. When the temperature of the water stops changing it's 16.4 °C. The pressure remains constant at 1 atm. Calculate the specific heat capacity of brass according to this experiment. Be sure your answer is rounded to 2 significant digits. П J g.°C x10 X S thermometer insulated container water sample a calorimeter U!!! 0 C

An 87.9 g sample of chromium metal at 99.1°C is placed in a calorimeter containing 100.00 g of water at 21.0°C The contents of the calorimeter come to a temperature of 25.7°C. The heat capacity of water is 4.18 J/(g* °C) a. Is this process exothermic or endothermic? b. Calculate the amount of heat released by the metal (q metal) in Joules. Show your work.

The enthalpy change for a chemical reaction is the sum of the energy consumed in breaking bonds and the energy released during bond formation. One way to determine the overall energy change for a chemical reaction is to apply Hess’s law to add together a group of reactions which can be arranged such that the chemical equations, when combined, give the overall equation we are trying to characterize.     a. Write a balanced chemical equation for the combustion of gaseous propane in gaseous oxygen to produce gaseous carbon dioxide and liquid water.      C3​H8​(g)+    O2​(g) ---->CO2​(g)+     H2​O(g)   b. Combine the following equations to determine the enthalpy change for the combustion of 1 mole of propane. Assume that solid carbon is graphite.  3C(s,graphite)+4H2​(g)--->C3​H8​(g) ΔHo = -103.8 kJ/mol   C(s,graphite)+O2​(g)--->CO2​(g) ΔHo= -393.5 kJ/mol   H2​(g)+1/2​ O2​(g)--->H2​O(g) ΔHo= -285.8 kJ/mol      kJ/mol…