Final answer:
To find the molar mass of the compound formed by metal M and chlorine, we add the atomic mass of M (56 amu) to the average atomic mass of chlorine (35.45 amu), resulting in a molar mass of 91.45 amu. The closest answer choice is 91.5 g/mol (option c).
Step-by-step explanation:
The question concerns the reaction of a metal M of atomic mass 56 amu (atomic mass units) with chlorine to form a compound, and what the molar mass of the resulting compound would be. We know that the atomic mass of chlorine is not 40 g/mol as mentioned in the 'wiki-phony' site, since the actual average atomic mass of chlorine is approximately 35.45 amu, considering the isotopic composition of chlorine-35 and chlorine-37.
To calculate the molar mass of the compound formed when metal M reacts with chlorine, assuming the formation of a compound with one atom of M and one atom of Cl, we would add the atomic mass of M (56 amu) to the average atomic mass of chlorine (35.45 amu). Therefore, the molar mass of the compound would be:
M + Cl = 56 amu + 35.45 amu = 91.45 amu
The closest option to this value would be 91.5 g/mol, which is option c. This molar mass means that one mole of the compound has a mass of 91.5 grams.