1.
SiO₂(s) + HF(aq)   H₂SiF₆(aq) + 2 H₂O

SiCl4 + Mg(s)   Si(s) + 2 MgCl2(aq)

2.

3.

zircon — ZrSiO₄
silane — SiH₄
quartz — SiO₂
trichlorosilane— SiHCl₃
silica — SiO₂
silicon carbide — SiC
dimethyldichlorosilane - SiCl₂(CH₃)₂
sodium silicate — Na₂SiO₃

4. list one: zircon, ZrSiO₄; willemite, Zn₂SiO₄; phenakite, BeSiO₄

5. carbon’s ability to form double bonds to oxygen and silicon’s lack thereof.

6. Carbon to Lead:

atomic radius increases
electrical conductivity increases
metallic character increases
mp decreases
first ionization energy decreases
electronegativity decreases
electron affinity decreases

7. silicon does not conduct electricity very well; it has a shiny, metallic appearance but brittle

8. in the form of some sort of silicate

9. (a) 4 oxygens and one silicon; (b) the charge is -4

10.

 
 

11a.

break 4 Si-C bonds  4 x 381 kJ
break 4 O-H bonds  4 x 467
form 4 Si-O   4 x -452
form 4 H-Cl   4 x -427
TOTAL   DH = -124 kJ

11b.

break 4 Si-C bonds  4 x 381 kJ
break 4 O-H bonds  4 x 467
form 4 Si-O single bonds! 4 x -452
form 4 H-Cl   4 x -427
TOTAL    DH = -124 kJ

12.

Si-O = 452 kJ/mol (pg 149); C-C = 347; although the Si-O bond is very strong, there are several bonds stronger: B-O, B-F, H-F, etc.

14. Ca(OH)₂(aq) + CO₂(aq)  CaCO₃(s) + H₂O(l) (Note: The actual reaction chemistry is far more complicated:  The CO₂ sets up an equilibrium with H₂CO₃.  The Ca(OH)₂(aq) is a base and thus partially or fully dissociated into Ca⁺²(aq) and OH^-(aq).  Depending on the pH, the H₂CO₃ is likely present as HCO₃- which reacts with Ca⁺², etc.)

15. purity = 99,999,999,999/100,000,000,000
 

% purity = 100% x 99,999,999,999/100,000,000,000 = 99.999999999%

11 nines pure!

Si₂Cl₆ + H₂O  Cl₃Si-O-SiCl₃ + H₂(?)

17. (a) figure below; (b) Si₃O₉^-6; n = 6; (c) BaTiSi₃O₉

18. Without the trace of CH₃SiCl₃ present, the chains are only linear as per left figure.  With trace amounts of CH₃SiCl₃ present, the chains will cross-link as per right figure:

19.

Vol = (542 pm)³ = 1.592 x 10⁸ pm³ = 1.592 x 10^-22 cm³

There are 8 silicon atoms per unit cell

m_Si = 3.732 x 10^-22 g Si

d = 3.732 x 10^-22 g Si/1.592 x 10^-22 cm³ = 2.344 g/cm³