An empty weighing dish has a mass of 1.0041 ± 0.0002 g. After you add dried sodium chloride to the dish, the mass is 3.2933 ± 0.0002 g. You quantitatively transfer the sodium chloride into a 500.00 ± 0.05 mL volumetric flask and dilute to the mark with deionized water. The molar mass of sodium chloride is 58.440 g/mol. What is the absolute error in the concentration of the resulting solution? Report your answer normally to the correct number of significant figures with the correct unit.

The correct answer to the following question will be "0.0013%".

Explanation:

The given values are:

Weight of an empty dish = 1.0041 ± 0.0002 g

Weight of dish + sodium chloride (NaCl) = 3.2933 ± 0.0002 g

Weight of NaCl = 2.2892 ± 0.0002 g

Now,

Volume of the solution = 500.00 ± 0.05 ± 0.0002

                                      = 500.00 ± 0.0502 ml

So,

Molarity =

On putting the values in the above formula, we get

             =

             = ( ± ) × ( ± )

             = ( ± )

Now,

Absolute error =

                         = %

the answer to your question is c.

if you read the house of usher you should know that the house was haunted

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