Why does water take long to heat and long to cool down

Used the balanced equation 2h2+ o2 - -> 2h2o. if you have 7.2 grams of o2 , how many grams of h2o can you produce ?

What does the mass of 0.7891 mol of ferric oxide (fe2o3)

Consider the reaction of a(g) + b(g) + c(g) => d(g) for which the following data were obtained: experiment initial [a], mol/l initial [b], mol/l initial [c], mol/l initial rate, mol/l.s 1 0.0500 0.0500 0.0100 6.25 x 10^-3 2 0.100 0.0500 0.0100 2.50 x 10^-2 3 0.100 0.100 0.0100 1.00 x 10^-1 4 0.0500 0.0500 0.0200 6.25 x 10^-3 what is the rate law for the reaction?