cis and trans

What’s the difference between the structures (a) and (b)?

(a)	(b)

(2Z)-but-2-ene (PIN) cis-but-2-ene (2E)-but-2-ene (PIN) trans-but-2-ene

Enantiomers

Have a look at the structures (a) and (b).

(a)	(b)

(+)-amphetamine (trivial) d-amphetamine (trivial) dextroamphetamine (trivial) dexamfetamine (INN) (2S)-1-phenylpropan-2-amine (substitutive) (−)-amphetamine (trivial) l-amphetamine (trivial) levoamphetamine (trivial) levamfetamine (INN) (2R)-1-phenylpropan-2-amine (substitutive)