| Term | Definition |
|---|
| Energy | The capacity to do work or to produce heat |
| Law of conservation of energy/ 1st law of thermodynamics | Energy can be converted from one form to another but can neither be created nor destroyed. |
| Potential energy | Energy due to position or composition |
| Kinetic energy | due to the motion of the object |
| KE= | 1/2 mv^2 |
| Temperature reflects | random motions of the particles of a particular substance |
| Heat | Transfer of energy between objects due to a temperature difference. |
| Work | Force acting over a distance |
| Energy is __________ of pathway | independent |
| Heat and work are _______ on pathway. | dependent |
| Pathway | The way in which energy transfer is divided between work and heat. |
| Internal energy is linked to energy in _______. | Bonds |
| State function/ State property | A property of the system that depends only on its present state (independent of pathway) |
| Energy is/is not a state function? | Is a state function |
| Work and heat are/are not state functions? | Are not state functions |
| System | Area of focus |
| Exothermic | energy flows out of the system |
| Endothermic | Energy flows into the system |
| The energy gained by the surroundings must equal | the energy lost by the system |
| In an exothermic reaction, the products possess more/less potential energy than the reactants? | less |
| In an exothermic reaction, the _______ energy stored in chemical bonds is being converted to _______ energy via heat. | potential; thermal |
| The change in potential energy is | The difference between the energy required to break the bonds in the reactants and the energy released when the bonds in the products are formed. |
| In an exothermic reaction, the bonds in the products are ______ than those of the reactants. | Stronger |
| ΔE= | q + w |
| Always take the ________'s point of view. | system |
| Expansion of a gas is +/- work? | negative |
| Compression of a gas is +/- | positive |
| w= | -P ΔV |
| In the equation for work, P is the ______ pressure. | External |
| Conversion of work from L atm to joules: | (101.3 J/ (L atm)) |
| Enthalpy is comparable to the state function of ______. | heat |
| H= | E + PV |
| At constant pressure, ΔH= | q |
| For an endothermic reaction, ΔH is positive/negative. | Positive |
| Real gases behave like ideal gases at ______ temperatures and ______ pressures. | high temperatures; low pressures. |
| (KE)avg= | (3/2)RT |
| Molar heat capacity | Energy required to raise the temperature of 1 mole of a substance by 1 K. |
| Molar capacity of an ideal gas at constant volume= | (3/2)R |
| If a gas is heated at constant volume, _____ work occurs. | no |
| For an ideal gas, Cp=Cv+_____ | R |
| Polyatomic molecules have observed values for Cv that are significantly _______ than (3/2)R. | greater |
| Polyatomic molecules absorb energy to excite __________ and _____________ motions. | rotational, vibrational |
| R= J/(Kmol) | 8.3145 |
| As molecules become more complex, Cv __________. | Increases |
| When an ideal gas is heated whether the process occurs at constant volume or constant pressure, nCv ΔT= | ΔE |
| Regardless of pressure or volume, nCp ΔT= | ΔH |
| q=nC ΔT, using _____ or ______ depending on conditions. | Cp, Cv |
| At constant _________, ΔE=q | volume |
| At constant _________, ΔH=q | pressure |
| Calorimetry | The science of measuring heat |
| Heat capacity (C)= | heat absorbed/increase in temperature |
| heat capacity per gram of substance | specific heat capacity |
| heat capacity per mole of substance | molar heat capacity |
| In constant-pressure calorimetry, the change in enthalpy equals the | heat |
| heat gained/lost= | specific heat capacity x mass of solution x increase in temperature |
| specific heat of water= 1 cal=_____ joules per degrees celsius per gram | 4.18 |
| ΔE and ΔH are different if ________ changes | volume (number of moles) |
| In a ______ ____________ weighed reactants are placed inside a rigid steel container and ignited (constant volume). | bomb calorimeter |
| _______ ___________ states that the change in enthalpy is the same whether the reaction takes place in one step or in a series of steps. | Hess's Law |
| If the reaction is reversed, then the sign of ΔH... | is also reversed |
| If coefficients are multiplied by an integer, then ΔH | is multiplied by the same integer |
| Standard enthalpy of formation is | the change in enthalpy that accompanies the formation of 1 mole of a compound from its elements with all substances in their standard states. |
| What is the standard state? | A precisely defined reference state. |
| Standard state of a gas: | 1 atm |
| Standard state for a substance present in solution: | 1 M at pressure of 1 atm |
| Standard state for an element | 1 atm and usually 25 degrees Celsius |
| Standard state for: carbon is _______, oxygen and hydrogen are the __________, and methanol is _________. | graphite, diatomic gases, liquid |
| The enthalpy of formation for an element in its standard state is | zero |
| The enthalpy change for a given reaction can be calculated by subtracting the enthalpies of formation of the ________ from the enthalpies of formation of the __________. | reactants; products |
| Petroleum and natural gas were most likely formed from remains of ____________ ________________ that lived about ________ million years ago. | marine organisms; 500 |
| Petroleum is a thick, dark liquid composed mainly of __________. | hydrocarbons |
| Natural gas consists mostly of __________ but also contains _______, __________, and ________. | methane; ethane, propane, butane |
| Petroleum chains usually contain ____ to more than ______ carbons. | 5; 25 |
| The goal of boiling petroleum is to leave __________ fractions behind. | heavier |
| Gasoline contains _____ to ______ carbons | 5;10 |
| Pyrolytic (high temperature) cracking was used to break heavier __________ molecules into ___________ fractions. | kerosene; gasoline |
| To promote a smoother combustion, tetraethyl lead is a very effective _________ _________. | antiknock agent |
| _________ in gasoline has been phased out due to its damage to the environment, animals, and humans. | Lead |
| Coal forms from ___________ of plants (formula ________) that over time reduces in ________ and ________ content. | cellulose; oxygen, hydrogen |
| Four stages of coal: | lignite, subbituminous, bituminous, and anthracite |
| As ________ content increases in coal, the energy available from combustion increases. | carbon |
| Burning coal yields the formation of ________ __________ which can lead to acid rain. | sulfur dioxide |
| The _________ ____________ released when coal is burned has significant effects on the earth's climate. | carbon dioxide |
| The ___________ _____________ due to excessive amounts of carbon dioxide describes the high surface temperature on Earth due to the dense atmosphere. | greenhouse effect |
| When _________ is high, the heat of the sun is retained more | humidity |
| Potential energy sources: | sun, nuclear processes (fission and fusion), biomass (plants), and synthetic feuls |
| Treating coal at high temperatures with oxygen and steam to replace carbon-carbon bonds with carbon-hydrogen and carbon-oxygen bonds is called __________ and creates the possibility of a _______ fuel. | coal gasification; gaseous |
| Syngas: | mixture of carbon monoxide and hydrogen and methane gas to react with oxygen and produce heat |
| A __________ is a suspension of fine particles in a liquid. | Slurry |
| The only product of hydrogen combustion is | water |
| Three main problems with hydrogen as fuel: | costs of production, storage, and transport |
| On metal surfaces, H2 __________. | decomposes |
| Hydrogen has a very low ________ __________ and has a potential for __________. | boiling point; explosion |
| Oil shale consists of a complex carbon-based material called __________ contained in ________ __________ formations. | kerogen; porous rock |
| Ethanol is formed by _________ but cannot be used in the U.S. because it does not __________ easily at low temperatures | fermentation; vaporize |
| _____________ is used in race cars and is better for the air quality than gasoline. | Methanol |
| Seed oils are used to produce a ___________ oil composed of carbon and hydrogen which react with oxygen to produce carbon dioxide, water, and _______. | biodiesel; heat |
| Heat can take the forms of __________, _____________, or radiation. | convection, conduction |
| Hess's Law states that the change in enthalpy is the same whether the reaction takes place in one step or | a series of steps |
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