How does the body react when the outside temperature gets too hot

Can someone me with 3 and 4 plz. this is for masteries test.

For a research project, a student decided to test the effect of the lead(ii) ion (pb2+) on the ability of salmon eggs to hatch. this ion was obtainable from the water‐soluble salt, lead(ii) nitrate, which the student decided to make by the following reaction. pbo(s) + 2 hno3(aq) → pb(no3)2(aq) + h2o losses of product for various reasons were expected, and a yield of 86.0% was expected. in order to have 5.00 g of product at this yield, how many grams of pbo should be reacted? (assume that sufficient nitric acid, hno3, would be used.)

1.17 mol hcl and 2.5 mol naoh react according to the equation hcl + naoh -> nacl + h2o . if the limiting reactant is hcl, determine the amount of excess reactant that remains. answer in units of mol.