Number 3. c.
Number 4. a.
Number 5. d.
From the equation above the reacting ratio of KClO3 to O2 is 2:3 therefore the number of moles of oxygen produced is ( 4 x3)/2 = 6 moles since four moles of KClO3 was consumed
mass=relative formula mass x number of moles
That is 32g/mol x 6 moles =192grams
12.88 x 1000 = 12,880 g
4.77 x 1000 = 4770 cm³
D = mass / volume
D = 12,880 / 4770
D = 2.70 g/cm³
hope this helps!
