Which of these statements about gravity are true? Gravity helps us stay situated on Earth without floating away.
Gravity gives objects their mass.
Gravity holds our galaxy together.
Multiplying the mass of an object by the acceleration due to gravity gives the weight of the object.
Gravity helps scientists launch spacecraft out of Earth’s atmosphere.

gravity holds our galaxy together

Explanation:

that is why we don't levitate into the air

answer : (a) volume of the gas = 8.67 ×   l

                (b) second virial coefficient b = -1.21226 l/mole

solution :   given,     t = 300k

                                p = 20atm

                                z = 0.86

                                n = 8.2 mmoles = 8.2 × moles

                                r =   0.082 l atm/k/mol

        find,     (a) volume of gas   and (b) second virial coefficient b at 300k.

formula used :            

                          and            

(a)            

                    = \times 0.082\times 300}{20}[/tex]

                    = 8.67 ×   l

(b)      

                    = (0.00867-1) × 8.659

                    = - 8.5839 l/mole