What is the molarity of a solution that is 7.00% by mass magnesium sulfate and has a density of 1.071 g/mL?

0.623 M

Explanation:

Step 1: Given data

Step 2: Calculate the percent by volume (%m/v)

We will use the following expression.

Step 3: Calculate the molarity

7.50 g of magnesium sulfate are dissolved in 100 mL of the solution. The molarity is:

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