If a and b are directly proportional and the value of a becomes 1/4 as much ,what happens to the value of b

Becomes 1/4 as much

Explanation:

If a and b are directly proportional, this means we may write an equality between them if some proportionality constant, k, is included, so that:

The equation shows that:

And since k is a constant, this would imply that increasing a by some fraction would also require b to increase by the same fraction.

In the context of this problem, we're given that a becomes 1/4 as much, meaning b should also become 1/4 as much to keep the same proportionality constant, k.

since electrons are negative the answer is neagtaive

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