MATSE 259 Exam 1 With Complete Solutions

MATSE 400 Exam 1 Questions With
Answers
Moh's Hardness 10
diamond, C, C-C, strong 3D covalent bonds


Moh's Hardness 9
corundum, α-Al2 O3, Al-O (~50% covalent), O are close packed so high bond density


Moh's Hardness 8
topaz, Al2 Si O4 F2, Al-O and Al-F (~50% ionic), O and F are close packed, Al-F is stronger


Moh's Hardness 7
quartz, Si O2, Si-O (~50% ionic), more open crystal structure with a lower bond density


Moh's Hardness 6
orthoclase, K Al Si2 O8, Al-O; Si-O; K-O, bonded in 3D but cleavage planes drop hardness


Moh's Hardness 5
apatite, Ca5 (PO4)3 F, Ca-O (largely ionic), O has higher valence (2-) than F (1-) when bonded to Ca


Moh's Hardness 4
fluorite, Ca F2, Ca-F (largely ionic), low bond density


Moh's Hardness 3
calcite, Ca C O3, Ca-O (largely ionic), cleavage plane


Moh's Hardness 2
gypsum, Ca S O4 * 2(H2O), hydrogen bonds, covalently bonded layers connected by h-bonds


Moh's Hardness 1
talc, Mg3 Si4 O10 (OH)2, Van der Waals bonds, covalently bonded layers connected by VdW bonds


C-C bond length
1.54 A


puckered hexagonal ring
alternating up-pointing and down-pointing atoms arranged in a hexagon, diamond cleaves parallel to
this


isomorphs of diamond
C, Si, Ge