Asample of copper powder is heated in an evaporating dish using a bunsen burner. if the mass of the powder in the evaporating dish increases after heating, this indicates that a. the copper must have combined with another substance. b. the copper must have lost matter. c. hot copper is more dense than cold copper. d. hot copper weighs more than cold copper.

Answer : The correct option is, (A) the copper must have combined with another substance.

Explanation :

According to the question, when a sample of copper powder is heated in an evaporating dish by using Bunsen burner then the mass of the powder in the evaporating dish increases after heating that means the copper powder will be combined with the another substance.

If the mass of powder in the evaporating dish is decreases after the heating then the copper powder must have lost some matter.

The given option C and D are wrong statements because the hot copper is less dense than the cold copper and as we know that the density is directly proportional to the mass of a substance that means the hot copper weighs less than cold copper.

Hence, the correct option is, (A) the copper must have combined with another substance.

може ли да зареждате повече информация, моля

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