Term
| ΔE(change in internal energy) |
|
Definition
+ engergy flows into the system
-energy flows out of the system |
|
|
Term
| ΔE(the change in the internal energy of the system) |
|
Definition
| q(heat transferred)+w(the work done) |
|
|
Term
| Thermal energy always flows from matter at ____ temperatures to matter at _____ temperatures. |
|
Definition
|
|
Term
|
Definition
| no additional net transfer of heat |
|
|
Term
|
Definition
| The constant of proportionality between q and ΔT; a measure of the system's ability to absorb thermal energy without undergoing a large change in temperature. the quanitity of heat required to change its temperature by 1 °C |
|
|
Term
| specific heat capacity (Cs) |
|
Definition
| the intrinsic capacity of a substance to absorb heat. the amount of heat required to raise the temperature of 1 g of the substance by 1 °C. |
|
|
Term
| What are the units of specific heat capacity? |
|
Definition
|
|
Term
|
Definition
| the amount of heat required to raise the temperature of 1 mole of a substance by 1°C. |
|
|
Term
| What are the units of molar heat capacity? |
|
Definition
|
|
Term
| Is heat capacity an intensive or extensive property? |
|
Definition
| Extensive, it depends on the amount of matter being heated. |
|
|
Term
| Is specific/molar heat capacity an intensive or extensive property? |
|
Definition
| intensive, it despnds on the kind of substance being heated not the amount. |
|
|
Term
equation that shows the relation ship between the amount of heat added to a given amount of substance and the corresponding temperature increase.
q(heat in J)= |
|
Definition
| m(mass in g)×Cs (specific heat capacity J/g·°C)×ΔT(temperature change in °C) |
|
|
Term
|
Definition
| occurs when the force is cause by a volume change against an external pressure |
|
|
Term
pressure-volume work equation:
w= |
|
Definition
| -P(pressure)×ΔV(change in volume) |
|
|
Term
|
Definition
| qv(heat at constant volume) |
|
|
Term
|
Definition
| a piece of equpiment designed to measure ΔE for combustion reactions |
|
|
Term
temperature change and heat absorbed by the entire calorimeter assembly equation:
qcal= |
|
Definition
|
|
Term
If no heat escapes from the calorimeter,
qcal = |
|
Definition
|
|
Term
| To get ΔErxn per mole of a particular reactant |
|
Definition
| divide qrxn by the number of moles that actually reacted. |
|
|
Term
|
Definition
| the sum of the system's internal energy and the product of its pressure and volume |
|
|
Term
|
Definition
|
|
Term
ΔH(change in enthalpy) for any process occurring under constnat pressure:
ΔH= |
|
Definition
ΔE +PΔV
or essentially:
qp |
|
|
Term
|
Definition
| a chemical reaction with a positive ΔH, absorbs heat from its surroundings. |
|
|
Term
|
Definition
| a chemical reaction with a negative ΔH, gives off heat to its surroundings. |
|
|
Term
| If an endothermic reaction absorbs heat, then why does it feel cold to the touch? |
|
Definition
| when you touch the vessel in which the reaction occurs, you, being part of the surroundings lose heat to the system(the reaction), which makes you feel cold. |
|
|
Term
| Is ΔHrxn(enthalpy of reaction)an intensive or extensive property? |
|
Definition
| It is an extesnive property, one that depsnds on the amount of material undergoing the reaction. The amount of heat generated or absorbed hen a chemical reaction occurs depnds on the amounts of reactants that actually react. |
|
|
Term
| Bomb calorimetry occurs at constant ____ and measures Δ__ for a reaction |
|
Definition
|
|
Term
| coffee-cup calorimetry occurs at constant _____ and measures Δ__? |
|
Definition
|
|
Term
| If a chemical equation is multiplied by some factor, then ΔHrxn.... |
|
Definition
| is also multiplid by the same factor. |
|
|
Term
| If a chemical equation is reversed then ΔHrxn ... |
|
Definition
|
|
Term
|
Definition
| the change in enthalpy for a stepwise process is the sum of the enthalpy changes of the steps. |
|
|
Term
| The standard state for a gas |
|
Definition
| the pure gas at a pressure of exactly 1 atmosphere |
|
|
Term
| The standard state for a liquid or solid |
|
Definition
| is the pure substance in its most stable form at a pressure of 1 atm and at the temperature of interest (often taken to be 25°C) |
|
|
Term
| The standard state for a substance in solution |
|
Definition
| is a concentration of exactly 1 M |
|
|
Term
standard enthalpy change (ΔH°)
|
|
Definition
| the change in enthalpy for a process when all reactants and products are in their standard states. |
|
|
Term
| Standard enthalpy of formation (ΔHf °) for a pure compound: |
|
Definition
| the change in enthalpy when 1 mole of the compound forms from its constituent elements in their standard states. |
|
|
Term
| standard enthalpy of formation (ΔHf °) for a pure element in its standard state |
|
Definition
|
|
Term
|
Definition
| subtract the enthalpies of formation of the reactants multiplied by their stoichiometric coefficients from the enthalpies of formation of the products multiplied by their stoichiometric coefficients. |
|
|
