Energetics Questions and Answers

The rate constant for the reaction is 0.260 M-¹. s-¹ at 200 °C. A → products If the initial concentration of A is 0.00140 M, what will be the concentration after 605 s?

We have a bomb calorimeter with a heat capacity of 555 J/K. In this bomb calorimeter, we place 1000.0 mL of water. We burn 2.396 g of a solid in this bomb calorimeter. The temperature of the bomb calorimeter and the water increases by 2.12 °C. The molar mass of the solid is 553.0 g/mol. How much heat (in kJ) will be released if we were to burn 0.148 mol of this same solid in the bomb calorimeter? Keep in mind that we want to find the amout of heat released. The specific heat capacity or water is 4.184 J/K/g. Approximate the density of water as being exactly 1.00 g/mL.

Dietheyl ether has a vapor pressure of 0.991 torr at -73.9℃. The heat of vaporization is Δvap = 34.0 kJ/mol What is the vapor pressure at 9.4 C in torr? Do not write unit in answer. Report your answer as a whole number.

The heat of fusion for sodium (Na) is 2.6 kJ/mol. How much heat is needed to melt 46 grams of Na at its melting point of 98 °C? 1.3 kJ 5.2 kJ 49.0 kJ 19 kJ

Which process is accompanied by an increase in the entropy of the system? the condensation of water on cold surface the freezing of a popsicle solid gold melting sewing a quilt a cup of coffee cooling in a mug

All liquids evaporate to a certain extent. The pressure exerted by the gas phase in equilibrium with the liquid is called vapor pressure, Pvap. The vapor pressure of a particular substance is determined by the strength of the intermolecular forces. But for any given substance, the vapor pressure only changes with temperature. The Clausius-Clapeyron equation expresses the relationship between vapor pressure and temperature: AHvap In P₂ = In P₁ + (H) (#) R where P2 and P₁ are the vapor pressures that correspond to temperatures T2 and T₁, respectively, A Hvap is the molar heat of vaporization, and R= 8.3145 J/(mol. K) is the gas constant. The vapor pressure of dichloromethane, CH₂Cl2, at 0 °C is 134 mmHg. The normal boiling point of dichloromethane is 40. C. Calculate its molar heat of vaporization. Express your answer to three significant figures and include the appropriate units.

A styrofoam calorimeter contains 70.0 mL of 2.50 M NaOH at 20.3°C. When 10.28 g H2C2O4 is added to the calorimeter, the temperature of the resulting solution increases to a maximum of 44.7°C. The reaction that occurs is: H₂C2O4(s) + 2 NaOH(aq) → Na2C₂O4 (aq) + 2 H₂O(l) What is the (experimental) enthalpy change for this reaction, ΔH ? (Use the total mass of solution and 4.18 J/(g°C) for the specific heat of the solution in your calculations.)

Rashaun adds a white crystalline solid to water in a beaker. When he picks up the beaker, he observes it feels cold to the touch. If we define the white crystalline solid and the water as the system and the beaker and Rashaun's hand as the surroundings, then heat flows from the _ to the _ The process that occurs between the white crystalline solid and the water is If no work is done during this process, the change in internal energy, ΔE, is _ and the internal energy of the system _.

Given: H₂(g) + Br₂(1)→ 2 HBr(g) ΔHx= -72.8 kJ Calculate the amount of energy absorbed or released when 15.0 g of HBr(g) is formed. 4.85 kJ absorbed 6.75 kJ released 13.5 kJ released 607 kJ absorbed

If 1.17 g of glucose are burned in a bomb calorimeter, the temperature of the 900. g of water in the calorimeter increases from 15.90 °C to 20.20 °C. If the heat capacity of the calorimeter is 460. J/oC what is the value of q for the combustion of the glucose sample? • Use Cwater = 4.184 J/gC • Report your answer using three significant figures.

A chemist fills a reaction vessel with 8.15 atm nitrogen monoxide (NO) gas, 4.02 atm chlorine (Cl₂) gas, and 6.09 atm nitrosyl chloride (NOCI) gas at a temperature of 25.0°C. Under these conditions, calculate the reaction free energy ΔG for the following chemical reaction: 2NO(g) + Cl₂ (g) <--> 2NOCI(g) Use the thermodynamic information in the ALEKS Data tab. Round your answer to the nearest kilojoule.

Describe the phase and temperature changes that will occur if you heat 50.0 g of Compound X in its solid state at -8°C until it all vaporizes. You may draw a diagram or graph if it helps answer the question. Calculate the amount of heat needed for each step of the process you described in part 1, and then calculate the total amount of heat required.

In the reaction of aluminum and iron(III) oxide to form iron and aluminum oxide, ΔH is -850 kJ. How many kJ are released when 10. g of Al react? 2 Al(s) + Fe₂O3 (s) → 2 Fe (s) + Al₂O3 (s) ΔH= -850 kJ -1100 kJ -320 kJ -160 kJ -850 kJ

Calculate the energy (J) change (ΔE) associated with an electron transition from n=2 to n = 7 in a Bohr hydrogen atom. A) 5.01 x 10-19 J B) 3.21 x 10-18 J C) 4.23 x 10-17 J D) 5.46 x 10-16 J E) 6.38 x 10-15 J

The following information is given for manganese at 1 atm: Tb = 2095.00°C Tm = 1244.00°C Specific heat solid = 0.4770 J/g °C Specific heat liquid = 0.8370 J/g °C ΔHvap (2095.00°C) = 4.090 × 10³ J/g ΔH fus fus (1244.00°C) = 266.5 J/g A 44.00 g sample of solid manganese is initially at 1219.00°C. If the sample is heated at constant pressure (P = 1 atm), _ kJ of heat are needed to raise the temperature of the sample to 1340.00°C.

In a calorimetry experiment, 0.1277 g of Mg ribbon was added to 200.0 mL 0.500 M HCl at 24.12 °C. The water temperature increased to 27.10 °C. Calculate AH per mole of HCI. (ans: -24.9 kJ/mol HCI)