Exam 6: Thermochemistry

An 8.21 g sample of glycerol (C₃H₈O₃, molar mass = 92.0938 g ) was combusted in a bomb calorimeter with a heat capacity of 10.61 kJ . If the temperature increased from 22.1 °C to 36.0 °C, determine U for the combustion of glycerol.

For a particular process that is carried out at constant pressure, q = 145 kJ and w = -35 kJ. Therefore, ________.

Match the following. -energy associated with the temperature of an object

Energy that is associated with the position or composition of an object is called

Calculate the final temperature of a 63.7 g piece of palladium, originally at 100.0 °C, placed inside a coffee cup calorimeter containing 115.0 mL of water at 21.8 °C. The specific heat capacity of water is 4.184 J g^-1 °C^-1, the specific heat capacity of palladium is 0.246 J g^-1 °C^-1, and the density of water is 1.00 g mL^-1.

The specific heat capacity of liquid mercury is 0.14 J . How many joules of heat are needed to raise the temperature of 4.00 g of mercury from 19.0°C to 39.5°C?

A 21.8 g sample of ethanol (C₂H₅OH) is burned in a bomb calorimeter according to the following reaction. If the temperature rises from 25.0 °C to 62.3 °C, determine the heat capacity of the calorimeter. The molar mass of ethanol is 46.07 g . C₂H₅OH(l) + 3O₂(g) → 2CO₂(g) + 3H₂O(g) U = -1235 kJ mol^-1

Calculate the kinetic energy of a 150 g baseball moving at a speed of 39. m ( 87 mph).

Calculate the mass of NH₄ClO₄, molar mass = 117.49 g mol^-1, required to create a temperature change of -1.0 °C in a coffee cup calorimeter containing 115 mL of water. The enthalpy of solution for NH₄ClO₄ is 33.47 kJ mol^-1. The specific heat of water is 4.184 J g^-1 °C^-1, and assume the density of the solution is 1.00 g mL^-1.

Calculate the final temperature of 6.84 g of praseodymium (specific heat capacity = 0.193 J g^-1 °C^-1) initially at 26.8 °C that releases 11.3 J of energy into the surroundings.

Match the following. -energy associated with the relative positions of electrons and nuclei in atoms and molecules

Using the following equation for the combustion of octane, calculate the amount of moles of carbon dioxide formed from 100.0 g of octane. The molar mass of octane is 114.33 g . The molar mass of carbon dioxide is 44.0095 g . 2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O H° = -11018 kJ

The specific heat capacity of solid copper metal is 0.385 J . How many joules of heat are needed to raise the temperature of a 1.55 kg block of copper from 33.0°C to 77.5°C?

Calculate the heat transfer (J) when 3.15 g of platinum (specific heat capacity = 0.133 J g^-1 °C^-1) at 86.1 °C cools to room temperature, 24.3 °C.

A 100.0 mL sample of 0.300 mol L^-1 NaOH is mixed with a 100.0 mL sample of 0.300 mol L^-1 HNO₃ in a coffee cup calorimeter. If both solutions were initially at 35.00 °C and the temperature of the resulting solution was recorded as 37.00 °C, determine the H° (in units of kJ ) for the neutralization reaction between aqueous NaOH and HNO₃ . Assume 1) that no heat is lost to the calorimeter or the surroundings, and 2) that the density and the heat capacity of the resulting solution are the same as water.

Calculate the enthalpy of solution for the dissolution of lithium iodide, LiI, molar mass = 133.85 g mol^-1. When 1.49 g of LiI is dissolved in a coffee cup calorimeter containing 75.0 mL of water the temperature increased from 23.5 °C to 25.7 °C. The specific heat of water is 4.184 J g^-1 °C^-1, and assume the density of the solution is 1.00 g mL^-1.

Two solutions, initially at 24.60 °C, are mixed in a coffee cup calorimeter (C_cal = 15.5 J °C^-1). When a 100.0 mL volume of 0.100 mol L^-1 AgNO₃ solution is mixed with a 100.0 mL sample of 0.200 mol L^-1 NaCl solution, the temperature in the calorimeter rises to 25.30 °C. Determine the Δ_rH° for the reaction as written below. Assume that the density and specific heat capacity of the solutions is the same as that of water. NaCl(aq) + AgNO₃(aq) → AgCl(s) + NaNO₃(aq) Δ_rH° = ?

A 6.55 g sample of aniline (C₆H₅NH₂, molar mass = 93.13 g ) was combusted in a bomb calorimeter with a heat capacity of 14.25 kJ . If the initial temperature was 32.9 °C, use the information below to determine the value of the final temperature of the calorimeter. 4C₆H₅NH₂(l) + 35O₂(g) → 24CO₂(g) + 14H₂O(g) + 4NO₂(g) ΔU° = -1.28 × 10⁴ kJ

Use the H° and H° information provided to calculate H° for IF: IF₇(g) + I₂(g) → IF₅(g) + 2IF(g) Δ_r H° = -89 kJ H° (kJ ) IF₇(g) -941 IF₅(g) -840

Calculate the work, w, gained or lost by the system when a gas expands from 15 L to 40 L against a constant external pressure of 1.5199 bar.