Assume the shape of a helium balloon to be a sphere of radius, r, equal to 9 m, at standard sea level conditions. the volume, v, of a sphere is expressed as v = (4pi/3)r^3. note the molecular weight of he is mhe = 4 kg/kmol and for air, mair = 29 kg/kmol.
a. calculate the density of the helium, phe, inside balloon and the weight of the balloon, w,
assuming the material of the balloon is negligible.
b. calculate the balloon's buoyant force, fb.
c. what is the name of the principle by which the helium balloon derives its lift force?

Select the correct answer. when carbon dioxide dissolves in water, it sometimes reacts with water to form carbonic acid as in this balanced equation: co2 + h2o → h2co3. if 495 milliliters of carbon dioxide at 25°c and 101.3 kilopascals reacts with excess water, what is the theoretical yield of carbonic acid? use the periodic table and the ideal gas resource a. 0.889 g b. 1.10g c. 1.27g d. 2.02g what's the answer! quick!

Achemist wants to extract copper metal from copper chloride solution. the chemist places 0.50 grams of aluminum foil in a solution containing 0.75 grams of copper (ii) chloride. a single replacement reaction takes place. (ii) chloride. a single replacement reaction takes place. which statement explains the maximum amount of copper that the chemist can extract using this reaction? a) approximately 0.36 grams, because copper (ii) chloride acts as a limiting reactant b) approximately 1.8 grams, because copper (ii) chloride acts as a limiting reactant c) approximately 0.36 grams, because aluminum acts as a limiting reactant d) approximately 1.8 grams, because aluminum acts as a limiting reactant

In the reaction h2co3 (aq) + 3nh3 (aq) = 2 nh4+ (aq) + co3 2-, how many electrons are transferred?