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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: staga on September 02, 2010, 05:16:09 PM

Title: Enthaply of formation
Post by: staga on September 02, 2010, 05:16:09 PM

Hello everyone,

I was wondering if anyone could help me with this question...

sodium bicorbonate is heated and decomposes into sodium carbonate, water vapour and CO2. The deltaH for this reaction is +64.6 kJ/mol.

Using enthalpys of formation, calculate the enthalpy of formation of sodium bicarbonate.

So far ive only come uo with a balanced equation..

NaHCO3+ heat→ 1⁄2 Na2CO3+ 1⁄2 H2O + 1⁄2 CO2    ∆H=+ 64.6 kJ/mol

Thanks,
-Dan

Title: Re: Enthaply of formation
Post by: ContinuousProcess on September 03, 2010, 12:58:04 AM

Quote from: staga on September 02, 2010, 05:16:09 PM

Using enthalpys of formation,

Use the enthalpies of formation. (For the other species involved.)

After it's a simple game of addition.

Title: Re: Enthaply of formation
Post by: opti384 on September 03, 2010, 03:22:22 AM

The overall enthalpy of the reaction will be [those of the products] - [those of the reactants].