What is the mass, in grams, of 9.01 x 1024 molecules of methanol (CH, OH) ?

480.6 g

Explanation:

Given data:

Number of molecules of methanol = 9.01 ×10²⁴

Mass in gram = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ molecules

9.01 ×10²⁴molecules ×1 mol /6.022 × 10²³ molecules

1.5 ×10¹ mol

15 mol

Mass in gram:

Mass = number of moles × molar mass

Mass = 15 mol × 32.04 g/mol

Mass = 480.6 g

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.

the answer to your question is c