Naturally occurring zirconium exists as five stable isotopes: 90Zr with a mass of 89.905 amu (51.45%); 91Zr with a mass of 90.906 amu (11.22%); 92Zr with a mass of 91.905 amu (17.15%); 94Zr with a mass of 93.906 amu (17.38%), and 96Zr with a mass of 95.908 amu (2.80%). Calculate the average mass of zirconium.

2b2t

explanation:

2b2t

i think its 100.

hope this !

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