Solid zinc oxide (ZnO) is added to hydrochloric acid (HCl) to form zinc chloride (ZnCl2) in water (H2O). How many moles of zinc chloride (ZnCl2) will be produced when 112 grams of zinc oxide (ZnO) is used? ZnO + 2HCl --> ZnCl2 + H2O

1.376 moles ZnCl₂

Explanation:

Based on the reaction:

ZnO + 2HCl → ZnCl₂ + H₂O

1 mole of ZnO reacts with 2 moles of HCl to produce 1 mole of ZnCl₂.

To solve this question we need to convert the mass of ZnO to moles using its molar mass (ZnO = 81.38g/mol). The moles of ZnO added are the moles of ZnCl₂ produced (1mole of ZnO produce 1 mole of ZnCl₂):

Moles ZnO = Moles ZnCl₂:

112g ZnO * (1mol / 81.38g) = 1.376 moles ZnCl₂

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

you need to stop taking that class