Many drain cleaners are a mixture of sodium hydroxide and aluminum filings. When these two substances mix in water , they react to produce enough heat to melt the fat in a clogged drain. The bubbles produced are hydrogen gas. The complete reaction occurs in two steps: step 1:Al(s)+NaOH(aq) —> Al(OH)3(s)+Na(aq)
step 2: Na+(aq)+H2O —> Na2O(s)+H2(g)
a) Classify step 1 of the reaction as: addition, displacement, or decomposition.
b) Is this an endothermic or an exothermic reaction?
c) Balance each equation for each step of the reaction.

The least penetrating form of radiation is

Consider a one meter long horizontal pipe with a constant 100 cm^2 cross sectional area. water flows rightward into the pipe at x = 0 with flow velocity 02m/sec at every point within the pipe intake area. at x=1, the rightward flow rate is 0.192 m/sec. assume the water is a conserved quantity in the pipe, so there must be a leak (a sink) somewhere in the pipe. 1. compute net volumetric flow of the source if the system to be in equilibrium. 2. now assume the pipe in the problem has no leaks. compute the net volumetric rate of change for the system.

Aprisoner is forced to go into one of three rooms, but he can choose which room. the first room is ablaze with fire. the second one is rigged with explosives that will go off as soon as he enters. the third contains a pair of lions who haven't eaten in years. which room should he choose to survive?