[base788]

Say you have 80% w/w sulfuric acid in water (i.e. 80 g sulfuric acid and 20 g of water). If the density of sulfuric acid is 1.84 g/mL then the volume of sulfuric acid is 43.48 mL ([80 g] / [1.84 g/mL]). With the density of water being 1 g/mL the total volume of the solution is 63.48 mL (43.48 mL + 20 mL) and the %w/v sulfuric acid is 126% (80 g / 63.28 mL). Is this a correct calculation?

I realize if you have the density of the 80% sulfuric acid solution you can simply multiply times the %w/w to get %w/v.

[Borek]

Say you have 80% w/w sulfuric acid in water (i.e. 80 g sulfuric acid and 20 g of water). If the density of sulfuric acid is 1.84 g/mL then the volume of sulfuric acid is 43.48 mL ([80 g] / [1.84 g/mL]).

So far so good.

With the density of water being 1 g/mL the total volume of the solution is 63.48 mL (43.48 mL + 20 mL)

No. You have correctly calculated volumes of pure water and pure sulfuric acid, but volumes are not additive. Volume of the mixture is not 63.48, but 57.90. There is no way to calculate it without using density tables (I am using CASC that have density tables built in).

and the %w/v sulfuric acid is 126% (80 g / 63.28 mL). Is this a correct calculation?

Correct result for %w/v is 138.2