The observed mass of the sun is 6.270 * 10 ^ 26 * g but the actual mass of sun is 5.97*10^ 24 kg . The percent error in measurement is 4.78 %

i would say b

explanation:

but i think i would need more information than that

the correct answer to this question is 2

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