What is the change in enthalpy for the following reaction? 2h2o2(aq) 2h2o(l) + o2(g) given: h2o: ∆h= -242 kj h2o2: ∆h= -609 kj a) -286 kj b) -572 kj c) 572 kj d) 286 kj

The number of moles of a given mass of a substance can be found without knowing its molecular formula or molar mass. true false

Insoluble sulfide compounds are generally black in color. which of the following combinations could yield a black precipitate? check all that apply. na2s(aq)+kcl(aq) li2s(aq)+pb(no3)2(aq) pb(clo3)2(aq)+nano3(aq) agno3(aq)+kcl(aq) k2s(aq)+sn(no3)4(aq)

Athe top of a hill, an athlete on a skateboard has x joules of mechanical energy. how much mechanical energy will she have at the bottom of the hill? ignore the effects of friction.