# PAG 3 Determination of an enthalpy change of reaction by Hess' law

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Method
Measurew 30cm^3 (excess) of 2.00moldm^-3 HCL into cup inside beaker, weigh sample bottle with 2.5-3g of K2CO3-measure the temperature then carefully add K2CO3 to the HCL and stir constantly, measure final temperature, reweigh sample bottle, calculate
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method 2
heat absorbed, repeat with 3.2-3.7g of KHCO3 and calculate the amount of KHCO3 to determine enthalpy change of reaction
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control variables
mass of K2CO3 and KHCO3, concentration of HCL, volume of HCL
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dependent variables
temperature change, mass change
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observations
gets hotter
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equations needed
q=mc(delta)t, deltaH=q/n, a=b-c
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evaluative points that increase the result
larger initial mass, if mass isn't weighed
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evaluative points that decrease the result
heat loss to surroundings
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## Other cards in this set

### Card 2

method 2

#### Back

heat absorbed, repeat with 3.2-3.7g of KHCO3 and calculate the amount of KHCO3 to determine enthalpy change of reaction

### Card 3

#### Front

control variables

### Card 4

#### Front

dependent variables

observations