How many quarters have the same value as 85 dimes? Use the equality 4 quarters = 10 dimes. a. 85 × 10 × 4

b. (85 – 10) / 4

c. 85 × (10/4)

d. 85 × (4/10)

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i would say b

explanation:

but i think i would need more information than that

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