How many atoms are in 3al(po₄)

Explanation:

The compound shown is:

That means that there are 3 units of    .

Each unit of   . contains:

Thus, in total, there are 6 atoms in one unit of  .

The coefficient in front of the chemical formula indicates the number of units. Thus, there are 3 units, each with 6 atoms, for a total of 3 × 6 = 18 atoms.

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