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A particular sample of cold graphite at 10.20 °C was added to 988.5 g of water at 25.31 °C in a constant pressure calorimeter. If the final temperature of the graphite and water was 25.17 °C, what was the mass of the graphite sample? Assume no heat was lost to the surroundings. The specific heat for water is 4.184 J/g•°C and the specific heat for this graphite is 0.7069 J/g•°C.

22.214 g of a metal at 99.73°C was added to 14.2 g of water at 19.05°C. The temperature of the mixture rose to 28.78°C. What is the specific heat of the metal?  SH2O = 4.184 J/g°C

The reaction of zinc with hydrochloric acid is represented by the reactionZn(s) + 2 HCl(aq) ↔ ZnCl 2(aq) + H 2(g) -- ΔH = -152.5 kJ How many grams of zinc reacted with an excess of HCl (100.0 mL) if the temperature of the calorimeter increased from 25.0°C to 35.85 °C? Assume the heat capacity of the solution is the same as pure water (4.184 J/g*°C), the density of the solution is 1.00 g/mL and there is no loss of heat to the surroundings.

When 6.54 grams of Zn is placed in 500.0 mL of 1.00 M CuSO4(aq) in a coffee cup calorimeter, it reacts completely to displace copper. The temperature of the solution rises from 20.0˚C to 30.4˚C. Assume the coffee cup itself gains no heat and that the solution has the same density (1.00 g/mL) and specific heat (4.184 J/g˚C) as pure water. (a) How much heat does the solution gain during this reaction? (in J)

Use the following information to calculate the amount of heat involved in the complete reaction of 7.20 g of carbon to form PbCO3(s) in reaction 4. Be sure to give the proper sign (positive or negative) with your answer. Reaction 1 Pb(s) + O₂(g) PbO(s) Reaction 2 C(s,graphite) + O₂(g) →→→ CO₂(g) Reaction 3 PbCO3(s). PbO(s) + CO₂(g) Reaction 4 Pb(s) + C(s,graphite) + O₂(g) →→→ PbCO3(s) 1st attempt AH rxn4° = ? kJ AH rxnl AHO rxn2 AHO rxn3 AHXn4 = -219 kJ = - 394 kJ = 86 kJ = ? See Periodic Table See Hint

Small amounts of oxygen gas can be produced in the laboratory by heating potassium chlorate, KClO3. Determine the enthalpy change for this reaction using known enthalpies of formation. 2 KClO3(s) → 2 KCl(s) + 3 O2(g)

4. 30.0 g of a substance (molar mass: 46 g/mo) required 262 J of heat to raise its temperature from 32.0°C to 37.4°C. What is the specific heat per gram and per mole of this substance?

Hot water heaters often use natural gas (methane) to generate heat. Methane and oxygen react to form carbon monoxide according to the overall equation: 2CH4(g)+3O2(g) = 2CO(g)+4H2O(g) The enthalpy of formation for each compound are as follows: CH4: - 74.6 O2: 0 CO: - 110.5 H2O: - 285.8 Part A: calculate the overall enthalpy change of the reaction. Part B: A typical water heater contains 40.0 gallons of water. After a long vacation, you come home and turn your water heater from "vacation mode" to hot. How many moles of methane must be combusted to heat the water in your water heater from 30.0°C to 48.0°C? The density of water is 3.79 kg/gal, the specific heat capacity of water is 4.182 J/g°C, and the water heater has a heat capacity of 850.0 J/g°C.

The specific heat of substance C is 0.93 J/(g K) and that of substance D is 1.8 J/(g K). You are given an unknown that could be pure substance C, pure substance D, or a homogeneous mixture of C and D. In the lab you determine that it requires 23.3 J of heat energy to raise the temperature of a 25.0 g sample of the unknown by 1.0 K. What conclusions can you make about the identity of your unknown, from this data?