Q1a: What is the change in internal energy of a system (ΔU) if 5.42 kl of heat is absorbed by the system and 3425 J of work is done on the system (by the surroundings) for a certain process? Expess your answer in kJ 1b: A sample of oxygen gas (O₂) effuses into a vacuum 1.8 times faster than an unknown gas. What is the molecular weight of this unknown

An 80.0 g sample of a gas was heated from 25 °C to 225 °C. During this process, 346 J of work was done by the system and its internal energy increased by 9095 J. What is the specific heat of the gas?

A 57.0g sample of aluminum is put into a calorimeter (see sketch at right) that contains 250.0g of water. The aluminum sample starts off at 96.9°C and the temperature of the water starts off at 23.0°C. When the temperature of the water stops changing it's 26.2°C. The pressure remains constant at 1atm.   Calculate the specific heat capacity of aluminum according to this experiment. Be sure your answer is rounded to 2 significant digits.        Please type answer note write by hend.

A piece of metal of mass 15 g at 99◦C is placed in a calorimeter containing 41.3 g of water at 19◦C. The final temperature of the mixture is 40.2◦C. What is the specific heat capacity of the metal? Assume that there is no energy lost to the surroundings. Answer in units ofJg·◦C.

A researcher studying the nutritional value of a new candy places a 6.00 g6.00 g sample of the candy inside a bomb calorimeter and combusts it in excess oxygen. The observed temperature increase is 2.89 ∘C.2.89 ∘C. If the heat capacity of the calorimeter is 45.80 kJ⋅K−1,45.80 kJ⋅K−1, how many nutritional Calories are there per gram of the candy?

A 56.5 g sample of iron is put into a calorimeter (see sketch at right) that contains 300.0 g of water. The iron sample starts off at 86.7 °C and the temperature of the water starts off at 21.0 °C. When the temperature of the water stops changing it's 22.8 °C. The pressure remains constant at 1 atm. Calculate the specific heat capacity of iron according to this experiment. Be sure your answer is rounded to 2 significant digits. J 0₂-C x10 x thermometer insulated container water sample a calorimeter

a You want to determine the value for the enthalpy of formation of CaSO4(s). Ca(s) + S(s) + 2 O₂ (g) → CaSO4(s) This reaction cannot be done directly. You know, however, that both calcium and sulfur react with oxygen to produce oxides in reactions that can be studied calorimetrically. You also know that the basic oxide CaO reacts with the acidic oxide SO3 (g) to produce CaSO4(s) with A₁ H° = -402.7 kJ. Outline a method for determining A₁H˚ for CaSO4(s), and identify the information that must be collected by experiment. Using enthalpy of formation data, confirm that AƒH° for CaSO4(s) = −1433.5 kJ/mol. What compound is formed when Ca and O2 react?

A sample of iron, which has a specific heat capacity of 0.449 J.g¹.°C¹, is put into a calorimeter (see sketch at right) that contains 100.0 g of water. The iron sample starts off at 98.2 °C and the temperature of the water starts off at 23.0 °C. When the temperature of the water stops changing it's 27.4 °C. The pressure remains constant at 1 atm. Calculate the mass of the iron sample. Be sure your answer is rounded to 2 significant digits. 1 g x10 X 5 thermometer. insulated container water sample a calorimeter

A bomb calorimeter, or a constant volume calorimeter, is a device often used to determine the heat of combustion of fuels and the energy content of foods. In an experiment, a 0.3215 g sample of phenanthrene (C14H10) is burned completely in a bomb calorimeter. The calorimeter is surrounded by 1.162×10 g of water. During the combustion the temperature increases from 25.15 to 27.48 °C. The heat capacity of water is 4.184 J glc-!. The heat capacity of the calorimeter was determined in a previous experiment to be 769.3 J/°C. Assuming that no energy is lost to the surroundings, calculate the molar heat of combustion of phenanthrene based on these data. C14H10(s) + (33/2) O,(g) – → 5 H,O(1) + 14 CO2(g) + Energy Molar Heat of Combustion = kJ/mol

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