1. Calculate the volumes of the samples used in Procedure step 2. Record the calculated volumes in Table 2.2. Why could we not find the volume of the bolt by this method? 2. How did you find the volume of the PE rod using the displacement method? Note: 1 cm3 = 1 mL. Because PE floats, push the rod under the water with a very small object, such as a pin, and volume of the pin is negligible and can be ignored. 3. Except for the bolt, note the difference between the calculated volumes and the volume found by the displacement method. Which method is more accurate? Why?

that's what i got you can count the number of atoms

b. is the answer hoped i        

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