Holding temperature constant, how does molecular weight of a gas affects speed of sound?

If molecular weight is  increased the sound speed will decrease

Explanation:   The sound speed in an ideal gas is given by the relationship

v =√((γRT)/M)

When,

R - gas constant = 8.314 J/mol⋅K;

T - the total temperature

M - the molar mass of  gas in kg/mol

γ = adiabatic constant of specific gas.

this equation can also be explained as

v2 =((γRT)/M)

So, when T is constant , V squared is inversely proportional to M

Let us use example as an  illustrate

assuming that

1st (γRT)= 2 and M= 5

V will be

v2=2/5=0.4=0.632

2nd (γRT)= 2 and M= 10 (notice that we have increased M)

thus

v2=2/10=0.2=0.447

inconclusion, if you increase M(molecular weight) the speed of sound will decrease

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of these invertebrate animals also have an outer shell to protect their

body. oysters, clams, snails, and mussels are all mollusks. so are octopuses, squids, and slugs. mollusks live on land and in freshwater.