A voltaic cell with Ni/Ni2+ and Co/Co2+ half-cells has the following initial concentrations: [Ni2+] = 0.80 M; [Co2+] = 0.20 M. What is the initial E cell ?

a:

by the combination of an unlimited number of elements

it would be b. 6co2 + 6h2o --> c6h12o6 + 6o2

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol