The soapy precipitate is the salt of a weak base. Addition of HCl will generate the free fatty acid which can then be neutralized by NaOH. The difference in the number of moles of HCl and NaOH required to reach the endpoint gives the number of moles of RCO2 which can then be used to calculate the mass present in the solid and the percentage of the metal content.

is it a purebred? it looks more like a red nose, but it doesn't have the red could it be a staffordshire bull terrior? unsure if that's the right name for it sorry

not clear

12 is it do you think so

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