n the laboratory a "coffee cup" calorimeter, or constant pressure calorimeter, is frequently used to determine the specific heat of a solid, or to measure the energy of a solution phase reaction. A student heats 63.03 grams of chromium to 98.03 °C and then drops it into a cup containing 79.71 grams of water at 23.19 °C. She measures the final temperature to be 28.85 °C. The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.57 J/°C. Assuming that no heat is lost to the surroundings calculate the specific heat of chromium.   Specific Heat (Cr) =  ____________J/g °C.

In an experiment, 26.5 g of metal was heated to 98.0°C and then quickly transferred to 150.0 g of water in a calorimeter. The initial temperature of the water was 22.5°C, and the final temperature after the addition of the metal was 32.5°C. Assume the calorimeter behaves ideally and does not absorb or release heat.

q represents the change in heat of a reaction or substance. The units of q are Joules (J) or kilojoules (kJ). For a well understood substance, we can calculate the specific heat which relates the mass of the substance in grams to the amount of heat in J required to raise that amount a certain temperature.  We call that specific heat.  The specific heat (Cs) of water is stated in the following way:  C s ( H 2 O ) = 4.186 J g ∘ C This means that it takes 4.186 J of energy to raise the temperature of 1g of water by 1ºC.  The relationship between q and Cs for a given substance is  where m is mass (g) and ∆T is the change in temperature in ºC (final temp - initial temp).  Calculate the heat change (q) in J when 4.297 grams of water is cooled from 3.967 ºC to -2.902 ºC. Enter your answer with one decimal place (tenths).  Pay careful attention to the sign of your answer.  The sign of ∆T is always the same as the sign for q.

6. Determine the mass of a sample of water in a coffee cup calorimeter if the final temperature is 65.7 °C, the initial temperature is 22.3 °C, and 27.6 kJ of heat is added to the water (specific heat of water is 4.184 J/g•K).

Calculate the heat of reaction (in J)

1 A piece of metal with a specific heat of 1.011 J/gºC is heated to 123.1ºC and then placed in 111.031 g of water which is at a temperature of 3.6 ºC. After a minute, the temperature of the water has stopped changing and is now 55.8ºC. Assuming that there are no heat losses to the container or surroundings, what is the mass of the piece of metal in grams? Assume that water has a specific heat of 4.184 J/gºC. Enter your answer with at least 3 sig figs.

Which of the reactions are exothermic? 2 Mg(s) + O,(g) → 2 MgO(s) + heat O NH, (g) + HCI(g) → NH,CI(s) + heat AgCl(s) + heat – Ag*(aq) + Cl¯(aq) 2 Fe, 0, (s) + 3 C(s) + heat → 4Fe(s) + 3 CO, (g) O C(graphite) + 0,(g) → CO,(g) + heat O CH, (g) + 20,(g) → CO,(g) + 2 H,O(1) + heat

2. A solid substance has a mass of 250 grams. It is cooled by 25.00°C and loses 4.937 kJ of heat. What is the specific heat capacity of the substance?

3. In this experiment, we have used 1.0 x 1.01 J/°C for the heat capacity of the coffee-cup calorimeter. Let us verify this number through the following experiment using only hot and cold water. Experimental procedure: Place 50 mL of water at 20.0 °C in the coffee cup calorimeter. i. ii. Add 50 mL of hot water at 98.0 °C to the calorimeter holding the cold water. ii. The Trof 58.0 °C was obtained through the temperature-time graph. Calculate the specific heat of the coffee cup calorimeter. Remember that the heat lost by the hot water was gained by the cold water as well as the calorimeter.

What is the heat of a reaction, in joules, with a total reaction mixture volume of 67.3 mL if the reaction causes a temperature change of 5.9 °C in a calorimeter? Assume that the reaction mixture has a density of 1.00 g/mL and a specific heat of 4.184 J/g-°C. The calorimeter has a heat capacity of 10.0 J/°C.