Which statement about alkenes is not correct（）
A They are hydrocarbons
B They are saturated
C They contain a C=C bond
D They form polymers
查看答案
Suggest the shape of the phosphine molecule, PH3（）
A. Trigonal planar
B. Trigonal pyramidal
C. Trigonal bipyramidal
D. Octahedral
Ethanol is soluble in water. The best explanation for this is（）
A. ethanol molecules form hydrogen bonds with water molecules
B. ethanol molecules form London （dispersion） forces with water molecules
C. ethanol molecules form permanent dipole interactions with water molecules
D. ethanol and water are miscible liquids
The ability of an atom in a covalent bond to attract electrons to itself is called its electronegativity.The greater the difference between the electronegativities of the two atoms in the bond, the mo
A. chlorine and bromine
B. chlorine and iodine
C. fluorine and chlorine
D. fluorine and iodine
Which of the following properties of the elements chlorine, bromine and iodine increases with increasing atomic number（）
A. Boiling temperature
Bond enthalpy
C. Electronegativity
D. First ionization energy
微信支付 
支付宝支付