An endothermic reaction will start when the required ΔH energy is received from the environment or solution.

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

The limiting reactant(s) appeared to be

Asolution of naoh has a concentration of 25.00% by mass. what mass of naoh is present in 0.250 g of this solution? use the periodic table in the toolbar if needed. 0.0625 g what mass of naoh must be added to the solution to increase the concentration to 30.00% by mass? g