What mass of each solute is present in 294 g of a solution that contains 4.86% by mass nacl and 7.54% by mass na2co3

In order to compute the mass of each solute in the sample, we simply multiply the percentage mass of each solute with the total mass of the solution. This is ad such:
Mass (NaCl) = 0.0486 x 294
Mass (NaCl) = 14.29 grams

Mass(Na₂CO₃) = 0.0754 x 294
Mass(Na₂CO₃) = 22.17 grams

I’d have to say no because without oxygen in the water the fish would all be dead. so if you want to fish for dead fish, pick the ponds with the lowest oxygen concentrations.