Strontium-90 has a half-life of 28.8 years. If you start with a 10-gram sample of strontium-90, how much will be left after 115.2 years?

11) burning your hand when accidentally touching a hot plate is an example of which heat transfer? a. conduction b. convection c. radiation d. none of these

The sum of the oxidation numbers in a neutral compound is always

The combustion of methane, ch4, releases 890.4kj/mol. that is, when one mole of methane is burned,890.4 kj are given off to the surroundings. this meansthat the products have 890.4 kj less than the reactants.thus, ah for the reaction = - 890.4 kj. a negative symbolforah indicates an exothermic reaction.ch (g) + 20 (g)> co2 (g) + 2 h0 (1); ah = - 890.4 kga) how much energy is given off when 2.00 mol of ch,are burned? b) how much energy is released when 22.4g of ch. areburned?