10. Identifying Redox Reactions using Oxidation Numbers a) H2SO4 + Ca(OH)2 → CaSO4 + 2H2O

b) 4 Fe(s) + 3 O2(g) → 2 Fe2O3(s)

c) C3H3(g) + 5 O2(g) → 3 CO2(g) + 4H2O(g)

d) CO2(g) + H2O(0) → H2CO3(aq)

e) Cr2O72- + C2H5OH → 2 Cr3+ + 3 CH3COOH + H20

f) 2 H2O2 (1) ► 2 H20 (g) + O2(g)

organisms are more likely to be more preserved in mud than sand because mud is moist and wet, while sand is very dry.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.