Four research teams measured the length of a rare whale, and what each team wrote in its team notebook is shown in the table below. Suppose a later and more reliable measurement gives 45.0 m for the length of the same whale. Decide which of the earlier measurements was the most
accurate, and which was the most precise.
team
what was written
in the notebook
most accurate
measurement
most precise
measurement
?
A
"55.m"
B
*50.0m +0.5m
с
*44.0m + 6.0%
D
o
"between 30 m and 40 m

Explanation:

Precision relates to instruments of measurement or scale . A scale measuring upto cm is less precise than an instrument measuring upto mm .

Here the first measurement appears to have been taken with an instrument measuring up to metre and the second measurement appears to have been taken with an instrument measuring up to decimeter . So second measurement is most precise .

Third measurement is closest to the actual measurement that is 45.0 m , so it is most accurate measurement .

where's the diagram?

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