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Chemical reactions are invariable associ...

Chemical reactions are invariable associated with the transfer of enery either in the form of heat or light. In the laboratory, heat energy I physical and chemical processes are measured with an instrument called caloriemter. Heat change in the process is calcualted as:
`q-msDeltaT," "s=`specific heat
`=cDeltaT," "c=` Heat capacity.
Heat of reaction at constant pressure is measured using bomb calorimeter.
`q_(V)=DeltaU=` Internal energy change
heat of reaction at constant pressure is measrued using simple or water calorimeter.
`q_(P)=DeltaH`
`q_(P)=q_(V)+PDeltaV`
`DeltaH=DeltaU+DeltanRT`
The amount of energy released during a chemical change depends on the physical state of reactants and products, te conditions of pressure, temperatrue and volume at which the reaction is carried out. the variation of heat of reaction with temperature and pressure is given by kirchhoff's equation:
`(DeltaH_(2)-DeltaH_(1))/(T_(2)-T_(1))=DeltaC_(P)," "(DeltaU_(2)-DeltaU_(1))/(T_(2)-T_(1))=DeltaC_(V)`.
Q. The specific heats of `I_(2)` in vapour and solid states are 0.031 and 0.055 cal/g respectively. The heat of sublimation of iodine at `200^(@)C` is 6.096 kcal `mol^(-1)`. the heat of sublimation of iodine at `250^(@)C` will be:

A

3.8 kcal `mol^(-1)`

B

4.8 kcal `mol^(-1)`

C

`2.28` kcal `mol^(-1)`

D

5.8 kcal `mol^(-1)`

Text Solution

Verified by Experts

The correct Answer is:
D
`I_(1)(s)hArrI_(2)(g)`
`DeltaC_(P)=(0.031-0.055)xx10^(-3)xx254`
`(DeltaH_(2)-DeltaH_(1))/(T_(2)-T_1)=DeltaC_(P)`
`(DeltaH_(2)-6.096)/(50)=(0.031-0.055)xx10^(-3)xx254`
`DeltaH_(2)=5.79` kcal `mol^(-1)`.
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Heat of reaction at constant pressure is………….. .

Chemical reactions are invariably associated with the transfter of energy either in the form of heat or light. In the laboratory, heat changes in physical and chemical processes are measured with an instrument called calorimeter. Heat change in the process is calculated as {:(q = ms DeltaT,,s =Specific heat),(=cDeltaT,,c =Heat capacity):} Heat of reaction at constant volume is measured using bomb calorimeter. q_(V) = DeltaU = Internal energy change Heat of reaction at constant pressure is measured using simple or water calorimeter. q_(p) = DeltaH q_(p) = q_(V) +P DeltaV DeltaH = DeltaU +DeltanRT For which reaction will DeltaH = DeltaU ? Assume each reaction is carried out in an open container.

Knowledge Check

  • Chemical reactions are invariable associated with the transfer of enery either in the form of heat or light. In the laboratory, heat energy I physical and chemical processes are measured with an instrument called caloriemter. Heat change in the process is calcualted as: q-msDeltaT," "s= specific heat =cDeltaT," "c= Heat capacity. Heat of reaction at constant pressure is measured using bomb calorimeter. q_(V)=DeltaU= Internal energy change heat of reaction at constant pressure is measrued using simple or water calorimeter. q_(P)=DeltaH q_(P)=q_(V)+PDeltaV DeltaH=DeltaU+DeltanRT The amount of energy released during a chemical change depends on the physical state of reactants and products, te conditions of pressure, temperatrue and volume at which the reaction is carried out. the variation of heat of reaction with temperature and pressure is given by kirchhoff's equation: (DeltaH_(2)-DeltaH_(1))/(T_(2)-T_(1))=DeltaC_(P)," "(DeltaU_(2)-DeltaU_(1))/(T_(2)-T_(1))=DeltaC_(V) . Q. Matht eh List-I and List-II and select the answer from the given codes:

    A
    `{:(A,B,C,D,E),(1,2,3,4,5):}`
    B
    `{:(A,B,C,D,E),(5,2,3,4,1):}`
    C
    `{:(A,B,C,D,E),(1,3,4,2,5):}`
    D
    `{:(A,B,C,D,E),(2,3,4,1,5):}`

  • Chemical reactions are invariable associated with the transfer of enery either in the form of heat or light. In the laboratory, heat energy I physical and chemical processes are measured with an instrument called caloriemter. Heat change in the process is calcualted as: q-msDeltaT," "s= specific heat =cDeltaT," "c= Heat capacity. Heat of reaction at constant pressure is measured using bomb calorimeter. q_(V)=DeltaU= Internal energy change heat of reaction at constant pressure is measrued using simple or water calorimeter. q_(P)=DeltaH q_(P)=q_(V)+PDeltaV DeltaH=DeltaU+DeltanRT The amount of energy released during a chemical change depends on the physical state of reactants and products, te conditions of pressure, temperatrue and volume at which the reaction is carried out. the variation of heat of reaction with temperature and pressure is given by kirchhoff's equation: (DeltaH_(2)-DeltaH_(1))/(T_(2)-T_(1))=DeltaC_(P)," "(DeltaU_(2)-DeltaU_(1))/(T_(2)-T_(1))=DeltaC_(V) . Q. What value of DeltaT should be used for the calorimetry experiment that gives the following graphical result?

    A
    `10^(@)C`
    B
    `25^(@)C`
    C
    `20^(@)C`
    D
    `35^(@)C`

  • Chemical reactions are invariable associated with the transfer of enery either in the form of heat or light. In the laboratory, heat energy I physical and chemical processes are measured with an instrument called caloriemter. Heat change in the process is calcualted as: q-msDeltaT," "s= specific heat =cDeltaT," "c= Heat capacity. Heat of reaction at constant pressure is measured using bomb calorimeter. q_(V)=DeltaU= Internal energy change heat of reaction at constant pressure is measrued using simple or water calorimeter. q_(P)=DeltaH q_(P)=q_(V)+PDeltaV DeltaH=DeltaU+DeltanRT The amount of energy released during a chemical change depends on the physical state of reactants and products, te conditions of pressure, temperatrue and volume at which the reaction is carried out. the variation of heat of reaction with temperature and pressure is given by kirchhoff's equation: (DeltaH_(2)-DeltaH_(1))/(T_(2)-T_(1))=DeltaC_(P)," "(DeltaU_(2)-DeltaU_(1))/(T_(2)-T_(1))=DeltaC_(V) . Q. The enthalpy change (DeltaH) for the reaction, N_(2)(g)+3H_(2)(g)to2NH_2(g) is -91.38 kJ at 298 K. The nternal energy change DeltaU at 298K is:

    A
    `-92.38kJ`
    B
    `-87.42kJ`
    C
    `-97.34kJ`
    D
    `-89.9kJ`

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    Chemical reactions are invariably associated with the transfter of energy either in the form of heat or light. In the laboratory, heat changes in physical and chemical processes are measured with an instrument called calorimeter. Heat change in the process is calculated as {:(q = ms DeltaT,,s ="Specific heat"),(=cDeltaT,,c ="Heat capacity"):} Heat of reaction at constant volume is measured using bomb calorimeter. q_(V) = DeltaU = Internal energy change Heat of reaction at constant pressure is measured using simple or water calorimeter. q_(p) = DeltaH q_(p) = q_(V) +P DeltaV DeltaH = DeltaU +DeltanRT The heat capacity of a bomb calorimeter is 500 JK^(-1) . When 0.1g of methane was burnt in this calorimeter, the temperature rose by 2^(@)C . The value of DeltaU per mole will be

    Chemical reactions are invariable associated with the transfer of enery either in the form of heat or light. In the laboratory, heat energy I physical and chemical processes are measured with an instrument called caloriemter. Heat change in the process is calcualted as: q-msDeltaT," "s= specific heat =cDeltaT," "c= Heat capacity. Heat of reaction at constant pressure is measured using bomb calorimeter. q_(V)=DeltaU= Internal energy change heat of reaction at constant pressure is measrued using simple or water calorimeter. q_(P)=DeltaH q_(P)=q_(V)+PDeltaV DeltaH=DeltaU+DeltanRT The amount of energy released during a chemical change depends on the physical state of reactants and products, te conditions of pressure, temperatrue and volume at which the reaction is carried out. the variation of heat of reaction with temperature and pressure is given by kirchhoff's equation: (DeltaH_(2)-DeltaH_(1))/(T_(2)-T_(1))=DeltaC_(P)," "(DeltaU_(2)-DeltaU_(1))/(T_(2)-T_(1))=DeltaC_(V) . Q. The heat capacity of a bomb calorimeter is 500 J/K. When 0.1g of methane was burnt in this calorimeter, the temperature rose by 2^(@)C . the value of DeltaU per mole will be:

    Chemical reactions are invariable associated with the transfer of enery either in the form of heat or light. In the laboratory, heat energy I physical and chemical processes are measured with an instrument called caloriemter. Heat change in the process is calcualted as: q-msDeltaT," "s= specific heat =cDeltaT," "c= Heat capacity. Heat of reaction at constant pressure is measured using bomb calorimeter. q_(V)=DeltaU= Internal energy change heat of reaction at constant pressure is measrued using simple or water calorimeter. q_(P)=DeltaH q_(P)=q_(V)+PDeltaV DeltaH=DeltaU+DeltanRT The amount of energy released during a chemical change depends on the physical state of reactants and products, te conditions of pressure, temperatrue and volume at which the reaction is carried out. the variation of heat of reaction with temperature and pressure is given by kirchhoff's equation: (DeltaH_(2)-DeltaH_(1))/(T_(2)-T_(1))=DeltaC_(P)," "(DeltaU_(2)-DeltaU_(1))/(T_(2)-T_(1))=DeltaC_(V) . Q. The enthalpy of fusion of ice is 6.02 kJ mol^(-1) . The heat capacity of water is 4.18Jg^(-1).^(@)C^(-1) . What is the smallest number of ice cubes at 0^(@)C , each containing one mole of water, that are needed to cool 500 g of liquid water from 20^(C) to 0^(@)C ?

    The heat of reaction at constant pressure is given by

    Heat of a reaction (Q) at constant pressure is equal to

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