How many molecules of hbr are present in 42.5 grams of hbr

HBr molar mass is 80.9 g/mol
this means in 80.9 g - 1 mol of HBr
1 mol consists of 6.022 x 10²³ molecules of HBr
that means in 80.9 g HBr there are 6.022 x 10²³ molecules of HBr
therefore in 42.5 g of HBr there are 6.022 x 10²³/80.9 * 42.5 
the number of HBr molecules are therefore - 3.16 x 10²³ HBr molecules

Bthats what im doing to and i figured it out it is b

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