a) C2H6
mc=12
mH = 1
1 mol C2 H6 ........2 x 12 + 6 x 1 = 30g
7 moli C2 H6 .........................X g >> X = (7 x 30)/1 = 210g
b) C2 H3 Cl 1 mol de C2 H3 Cl ..........(2 x12 + 3 x 1 +1 x 35,5) = 62,5g
X moli C2 H3 Cl.............................................440g
X = 440 /62 = 7,04 moli
c ) 1 mol ......22, 4 l (dm3)
X moli ......44, 8 x 10-3 dm3 >>> X =( 44,8/22,4) 10-3 = 2 * 10-3 moli
C2H2 masa molara (2 x 12 + 2 x 1) = 26 g / mol
1 mol C2H2 ........................26g
2* 10-3moli .......................Xg .............>> X = 26 x 2 * 10-3 = 52 * 10-3 g = 0,052 g