Identify the isotope that has atoms with 28 neutrons, 23 protons, and 23 electrons A. ^28 Ni
B. ^23 V
C. ^23 Mn
D. ^51 Sb
E. ^51 V

E. ^51 V

Atomic number (number of protons in the nucleus): 23

Atomic symbol (on the periodic table of the elements): V

Atomic weight (average mass of the atom): 50.9415

Density: grams per cubic centimeter

Phase at room temperature: Solid

Melting point: 3,470 degrees Fahrenheit (1,910 degrees Celsius)

Boiling point: 6,165 F (3,407 C)

Number of isotopes (atoms of the same element with a different number of neutrons): 2; one stable V-51; one radioactive V-50

Most common isotopes: V-51 (99.75 percent natural abundance)

where are the choice options?

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