Questions

Explanations

36 Which two particle diagrams each represent a sample of one substance?

(1) I and II            (3) II and III

(2) I and III           (4) II and IV

or all the same atoms

no mixtures

37 According to Table G, which substance forms an unsaturated solution when 80. grams of the substance are stirred into 100. grams of H₂O at 10.°C?

(1) KNO₃               (3) NH₃

(2) KI                      (4) NaCl

38 What is the concentration of AgCl in an aqueous solution that contains 1.2 x10^-3 gram of AgCl in 800. grams of the solution?

(1) 1.2 ppm         (3) 7.2 ppm

(2) 1.5 ppm         (4) 9.6 ppm

(0.0012g/800.g)  x 1,000,000

39 A sample of gas is in a rigid cylinder with a movable piston. The pressure of the gas is kept constant. If the Kelvin temperature of the gas is doubled, the volume of the gas is

(1) halved            (3) tripled

(2) doubled         (4) unchanged

direct relationship

40 What is the amount of heat required to completely melt a 200.-gram sample of H₂O(s) at STP?

(1) 334 J               (3) 66 800 J

(2) 836 J               (4) 452 000 J