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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: ph.r on September 29, 2009, 12:25:02 PM

Title: Zn + Cu(2+) -> Zn(2+) + Cu
Post by: ph.r on September 29, 2009, 12:25:02 PM

Hi,

I carried out this redox reaction and recorded the temperatures at regural intervals in a period of time.

Having to determine the enthalphy change DQ=mcDT equation could be used.

What would be m?
would it be the mass of zinc, the mass of CuSO4 or both?

THank you

Title: Re: Zn + Cu(2+) -> Zn(2+) + Cu
Post by: Yggdrasil on September 29, 2009, 12:55:02 PM

If you performed the reaction in water, the mass would be the mass of water and c would be the heat capacity of water.  Remember that during the reaction, your system is exchanging heat with its surroundings (the water), so measuring the change in temperature of the water tell you about the amount of heat released or absorbed by the reactants.

Title: Re: Zn + Cu(2+) -> Zn(2+) + Cu
Post by: ph.r on September 29, 2009, 01:03:23 PM

the reaction was not carried out in a water environment. The environment was aqueous because the solution was copper (II) sulphate. To this solution zinc powder was added.

so what is my mass?

Thank you in advance

Title: Re: Zn + Cu(2+) -> Zn(2+) + Cu
Post by: renge ishyo on September 29, 2009, 01:23:18 PM

An "aqueous" environment means that the reaction took place in water. Follow Yggdrasil's advice. It is good for the planet.

Title: Re: Zn + Cu(2+) -> Zn(2+) + Cu
Post by: kimyacı on October 02, 2009, 10:05:19 AM

 As far as I know, in open atmosphere condition ( P is constant) , DQ directly equal the reaction enthalpy DH = Qp.If you caarry out this reaction in a calorimeter, you will determine directly  the DH