A motorcycle traveling at 19 m/s starts to slow down steadily, then it stops completely in 10 seconds. What is the motorcycle acceleration? (meant to put this in physics sorry)

the answer is a for sure mark brainliest i had got this right on usatestprep

the answer is c.the valence of the atoms combine .

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