Aqueous sulfuric acid solutions containing 15.0 wt% H2SO4 and 80.0 wt% H2SO4 are mixed to form 60.0 wt% product solutions the 15% solution was in a laboratory in which the temperature was 77°F. The 80% solution had just been taken from a storage cabinet in an air-conditioned stockroom and was at a temperature of 60°F when the mixing occurred.

(a) The mass of the 15% solution is 2.30 lbm. What mass of 60% solution should be weighed out?

(b) Use Figure 8.5-1 to estimate the product solution temperature if the mixing is adiabatic.

(c) The product solution temperature eventually drops to (77°F). How much heat (Btu) is transferred from the solution to the laboratory air in this constant-pressure cooling process?

(d) Which would be safer—adding the 15% solution slowly to the 80% solution or vice versa? Use Figure 8.5-1 to justify your answer.