Determine the number of grams of magnesium oxide if you have 2.63 moles of magnesium oxide.

The number of grams of Magnesium oxide= 106 g

Given

2.63 moles of Magnesium oxide

Required

mass of Magnesium oxide

Solution

The mole is the number of particles contained in a substance

1 mol = 6.02.10²³

Moles can also be determined from the amount of substance mass and its molar mass

Mol = mass : Molar mass

Mass of Magnesium oxide(MgO, MW=40.304 g/mol) :

= mol x MW

= 2.63 x 40.304

= 106 g

b false

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.