Asample of sodium hydroxide (naoh) has a mass of 160.0 g. the molar mass of naoh is 40.00 g/mol. how many moles of naoh does this sample contain?

4.00 moles.

Explanation:

The formula to calculate moles of any substance is:

molar mass is the sum of atomic masses of each element present in the compound.

We are given that the compound is NaOH.

The molar mass if 40.00 g/mol.

mass of NaOH = 160.0g

putting values in the formula:

moles of NaOH =4.00 mol

i think the answer is terrae but not 100 percent sure. ▓▬▬ §

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