Which of the following describes how the mechanical advantage of a simple machine affects the amount of force needed for work? A. By decreasing the distance over which the input force is applied, less force is needed to do the same amount of work. B. By decreasing the distance over which the input force is applied, more force is needed to do the same amount of work. C. By increasing the distance over which the input force is applied, more force is needed to do the same amount of work. D. By increasing the distance over which the input force is applied, less force is needed to do the same amount of work.

the solar system used to have much dust particles option no d

a

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