Acetylene, C2H2, is used in welding torches. It releases a lot of energy when burned in oxygen. The combustion of one gram of acetylene releases 48.2 kJ. A 0.750-g sample of acetylene is burned in a bomb calorimeter (heat capacity = 1.117 kJ/°C) that contains 650.0 g of water. The final temperature of

The enthalpy of combustion of isooctane (C8H18), one of the many hydrocarbons in gasoline is 5.45 × 103 kJ/mol. Calculate the enthalpy change per gram of isooctane and per liter of isooctane (d = 0.688 g/mL).

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)

If 30.5 g of LiBr are dissolved 350.0 g of water at 20.0 °C in an insulated container, a temperature change is observed. The Δ H of solution of LiBr is -48.8 kJ/mol. Assuming that the specific heat of the solution is 4.184 J/(g C) and that no heat is gained or lost by the container, what will be the final temperature of the solution?

A piece of chromium metal with a mass of 24.50 g is heated in boiling water to 98.3 °C and then dropped into a coffee-cup calorimeter containing 82.3 g of water at 23.4 °C. When thermal equilibrium is reached, the final temperature is 25.7 °C. Calculate the specific heat capacity of chromium. (The specific heat capacity of liquid water is 4.184 J/g ⋅ K.)

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

8. Instant cold packs can be made from ammonium nitrate by mixing/reacting it with water (reaction shown below). When 1.25 g of NH4NO3 is dissolved in 25.0 g of water at 25.8 °C, the temperature of the water after the reaction is 21.9 °C. What is the enthalpy change (ΔH) for this reaction in units of kJ/mol of NH4NO3? The heat capacity of water is 4.18 ?/ ?℃ . NH4NO3(s)  → NH4+(aq) + ??3 − (aq)

An 80.0 g sample of metal, initially at 96.0 °C, is placed into 150.0 g of water initially at 26.0 °C in a calorimeter. The final temperature of the water is 28.1 °C. What is the identity of the metal? (The specific heat of water is 4.18 J/g °C.) Metal Aluminum Copper Iron Magnesium Silver Tin Titanium Specific Heat Capacity J/(g•°C) 0.90 0.38 0.45 1.00 0.23 0.32 0.52 A) Fe B) Sn C) Ag D) Cu

A chemist burned a sample of coal in a bomb calorimeter. Her results are below. Calorimeter's Heat Capacity 7.264 kJ/°C Mass of Coal Initial Temperature Final Temperature 0.100 g 22.07°C 25.37°C The sample of coal that the chemist placed in the bomb was dry but when she finished the test there was a small amount of water in the bomb. Where did this water come from and how does it affect her result? The water came from the water surrounding the bomb so her measured heat of combustion is for a closed system. The water was a product of combustion so her measured heat of combustion is for an open system. The water came from the water surrounding the bomb so her measured heat of combustion is for an open system. The water was a product of combustion so her measured heat of combustion is for a closed system.

Silane, SiH4, burns according to the reaction, SiH4 + 2O2 → SiO2 + 2H2O, with ΔH° = –1429 kJ. How much energy in kJ is released if 18.01 g of silane is burned?   Atomic Mass: Si: 28.086 g/mol H: 1.008 g/mol O: 15.999 g/mol   Round your answer to 2 decimal places.   Silane, SiH4, burns according to the reaction, SiH4 + 2O2 → SiO2 + 2H2O, with ΔH° = –1429 kJ. How much energy in kJ is released if 18.01 g of silane is burned?   Atomic Mass: Si: 28.086 g/mol H: 1.008 g/mol O: 15.999 g/mol   Round your answer to 2 decimal places.