3. What is the definition of acceleration? The change in velocity multiplied by the time of change
The change in speed
The change in velocity
The change in velocity divided by the time during which the change occurs

C. The change in velocity.

Explanation:

I'm sure it's that if not then feel free to tell me. :)

c. 75.7

i think that is the right

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