Achemist wishes to detect an impurity in a certain compound that she is making. there is a test that detects an impurity with probability 0.90; however, this test indicates that an impurity is there when it is not about 5% of the time. the chemist produces compounds with the impurity about 20% of the time; that is, 80% do not have the impurity. a compound is selected at random from the chemist’s output. the test indicates that an impurity is present. what is the conditional probability that the compound actually has an impurity?

the grams   of   barium that   are in   2.3 x 10^23   atoms of barium   is   52.4 g (answer c)

    calculation

mass = moles   of ba   x molar   mass of ba

  molar mass of ba from periodic table=   137.3 g/mol

  use the   avogadro's law   constant   to   calculate the moles of barium

  that   is     1 mole =   6.02   x 10^23 atoms

                    ? moles = 2.3 x 10^23   atoms

by cross   multiplication

=(1 mole   x 2.3x 10^23 atoms)   / 6.02   x10^23 atoms)=   0.382   moles

mass   is therefore = 137.3   g/mol x 0.382 mol = 52.4 ( answer c)

explanation:

answer; talc and gypsum;

d

explanation: