Which of the following statements about chemical bonds is correct ? A) a covalent bind is formed when metal atoms share electrons to achieve a stable electron arrangement

B) a metal reacts with a non-metal to form particles which are bonds together by intermolecular forces

C) an ionic bond is formed when a metal atom transfer electron to non-metal atom

D)covalent bonds are stronger than ionic bonds

 D) covalent bonds are stronger than ionic bonds

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