(4 Points) An element is made up of three isotopes, one of which (sºx has a % abundance of 3.09%, while the other two are unknown. If the mass of the three isotopes are 28x(mass = 27.9769), 29x(mass = 28.9765) and
30X(mass = 29.9738), and the atomic weight of the element is 28.0855 amu, what are the % abundances of
the other two isotopes?

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange

Cryolite, na3alf6(s), an ore used in the production of aluminum, can be synthesized using aluminum oxide. start this question by first balance the chemical equation.1.) balance the equation: - alo3(s)+naoh(l)+hf(> na3alf6+h2o(g). 2.) if 17.5 kilograms of al2o3(s), 51.4 kilograms of naoh(l), and 51.4 kilograms of hf(g) react completely, how many kilograms of cryolite will be produced? 3.)which reactants will be in excess, (al2o3, naoh, or hf) 4.)what is the total mass of the excess reactants left over after the reaction is complete in kg?

Sum of brother and sisters age is 26. four times the brothers age is subtracted from three times the sisters age, the difference is 8. what are the ages of the brother and sister?