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Energetics and Thermodynamics

Heat capacity

A 5.00 g sample of aluminum pellets (specific heat capacity = 0.89 J/°C · g) and a 10.00 g sample of iron pellets (specific heat capacity = 0.45 J/°C · g) are heated to 100.0°C. The mixture of hot iron and aluminum is then dropped into 97.7 g of water at 24.2°C. Calculate the final temperature of the metal and water mixtur

Chemistry Problem Set: Heat Energy and Temperature

The specific heat capacity of benzene is 1.74J/g*K. What is its molar heat capacity (Jmol*K)? What quanity of heat is required to raise the temperature of 50.00mL of water from 25.52 to 28.75C? The density of water at this temperature is 0.997 g/mL. When 108g of water at a temperature of 22.5C is mixed with 65.1g of wat

Molarity/ chemical equations, shapes

23) ....CrOsub2^- + ... OH^-...CrOsub4^2- + ...Hsub2O+ e^- When the equation for the half reaction above is balanced what is the ratio of the coefficient's OH^-: CrOsub2^-? a) 1:1 b) 2:1 c) 3:1 d) 4:1 e) 5:1 24) CuO(s) + Hsub2(g) <--- / ---> Cu(s) + Hsub2O(g) triangle H = -2.0kJ The Substances in

Gas Law Problem

Nitrogen and Hydrogen gases react to form Ammonia. A closed, rigid cylinder contains a total of 0.750 mol of gas at 25 degrees C and 1.10 atm before the reaction takes place; the mole ratio of hydrogen to nitrogen in the cylinder is 3:2. Determine the temperature and pressure of the gas in the cylinder at the end of the reaction

Enthalpy of Reaction and Endothermic or Exothermic Assessment

Write the equation for the combustion of 1 mole of ethanol in oxygen and calculate the enthalpy of reaction for this change given delta Hf(CO2) = -393.7Kj/mol delta Hf(H2O) = -285.9 Kj/mol and delta Hf(C2H5OH)=-227kj/mol. I s the reaction exothermic or endothermic?

Calculating Mass of Products of a Heating a Hydrated Salt

The mass of a crucible and a hydrated salt was to be 21.477g. The mass of the crucible and the anhydrous salt was 20.070g. The mass of the crucible was 17.985 g. a) Calculate the mass of the hydrated heated b) Calculate the mass of h2o lost from the hydrate during heating c) Calculate the percent water in the hydrate

Simple Entropy

Please help with the following problems. A) Define entropy. Why is entropy considered an absolute quantity? B) For each of the pairs of substances below, choose the one expected to have the greater absolute entropy. Explain your answer. Assume 1 mol of each substance. i) Cu(s) or C(graphite) at the same temperatu

Heat Conversion of Ice to Water

A sample of water weighing 125g releases 10.0 kcal of heat as it cools from 80.5ºC to 0ºC. It then releases another 10.0 kcal of heat as it freezes at this temperature. How many kcal of heat are needed in order to convert 125g of ice at 0º to water at 80.5ºC?

Specific Heat

How much heat is released when 250.0g of copper is cooled from 100.0ºC to 20.5º? The specific heat of copper is 0.0921 cal/gºC.

Thermodynamic Data and Standard Enthalpy of Decomposition

Use thermodynamic data to calculate the standard enthalpy of decomposition of liquid hydrogen peroxide into water and oxygen gas: H2O2(l)-->H2O(g) + 1/2 O2(g). Calculate the energy released by the decomposition of 1.0 g of 90% hydrogen peroxide solution. Molar mass of hydrogen peroxide = 34.0 g/mol. Estimate the final temperat

Calculating the entropy of argon

The experimental specific heat capacity of argon is 0.5213 J/g/K at a pressure of 1 atmosphere at 300 K. Argon's entropy at 300 K is 3.877 J/g/K. Use these data to calculate the entropy of argon at 500 K.

Estimating temperature inside a cylinder of an internal combustion engine

Estimate the temperature inside a cylinder of an internal combustion engine just after the spark has ignited the fuel. You are provided with the following list of assumptions. Assume the cylinder has a volume of 10 liters. Assume that the oxidant is air containing 20% oxygen. Assume that the fuel is octane (C9H18, molar mass = 1


When an explosive is detonated inside a shell or cartridge case, the explosion effectively takes places in a closed or fixed volume container. (The chemical decomposition is fast compared to the rate at which the projectile can gain velocity.) You can make an estimate of the explosion temperature if you assume a constant volume,

Enthalpy of Formation

Calcium metal burns according to the following equation: Ca(s) + 1/2 O2(g) --> CaO (s). When 1.00 g of calcium metal is burned in a constant pressure calorimeter with a heat capacity of 15.20 kJ/K, the temperature increases by 1.04 degrees Celcius. Calculate the enthalpy of formation of calcium oxide. Compare this answer with -

Chemistry - Calorimetry

Coal used to fire a power plant has an energy value of 13,250 Btu/lb. A 0.2500 g sample of this coal is combusted in a bomb calorimeter with a heat capacity of 4,589 J/K. Calculate the temperature rise of the calorimeter?

A simple problem set of 10 simple, short first year problems.

4. The term proof is defined as twice the percent of volume of pure ethanol in solution. Thus a solution that is 95% ethanol by volume is 190 proof. What is the molarity of ethanol in a 92 proof ethanol water solution? (density of ethanol is .8g/cm3; mol. wt. of ethanol is 46). 6. Find the mass percent of CuSO4 in a solut

Finding maximum temperature of water when aluminum is dropped in

A piece of aluminum with a mass of 234 grams is heated to a temperature of 231 degrees Celcius and then is dropped into 123 mL of 21 degrees celcius water. If no energy is lost to the surroundings, what will be the maximum temperature reached by the water?

2 Chemistry questions

1) The Zinc in a 1.200g sample of foot powder was precipitated as ZnNH4PO4. The strong heating of the precipitate yielded 0.4089g of Zn2P2O7. Calculate the mass percent of zinc in the sample of foot powder. 2. A mixture contains only sodium chloride and potassium chloride. A 0.1586g sample mixture was dissolved in water. It t

Calculation of bond energies and enthalpies.

You may wish to review the Laws of Thermochemistry and Endothermic and Exothermic Reactions before you begin. A table of single bond energies should be used as a help (available in most general chemistry text books). Estimate the change in enthalpy, DH, for the following reaction: H2(g) + Cl2(g) --> 2 HCl(g)

Ligand binding

Could you take a look at some problems that I have answered to see if I'm in the right direction. (a) Using this plot, estimate the enthalpy and entropy of binding for each protein to DNA. (b) What is the free energy change for the binding of WT1 and EGR1 to DNA at 25oC? (a) For each of the proteins: is the binding to

What equation is needed to find temperature?

Given the moment of inertia of 12C16O is 1.457e-46kgm^2, at what temperature would the population of particles in the J=4 state be 1/8 the population of molecules in the J=0 state?

Reaction Mechanism

A reaction occurs with the following stoichiometry A + P -> AP The concentration of A was measured versus time after mixing, the data are the following: [A](nM) Time (s) 50 0 40 100 30 229 20 411 10

Reaction Mechanisms

The reaction of a hyrogrn halide A with an olefin B to give product P according to the stoichiometric relationship: A + B -> P is proposed to occur by the following mechanism: 2A <-> A2 (fast to equilibrium) A + B <-> C (fast to equilibrium) A2 + C -> P + 2A (slow) (a) Based on this mechan

How many kilometers can you walk after eating 120 g of glucose ?

The enthalpy change involved in the oxidation of Glucose is -2880 kJ/mol. 25 % of the energy is available for muscular work. If 100 kJ of muscular work is needed to walk one kilometer, what is the maximum distance that a person will be able to walk after eating 120 g of glucose ?