【单选题】the primary reason for the malleability of metal is ( ).
A.
the nondirectional nature of metallic bonding
B.
the slide ability of planes of atoms in a metal under stress
C.
the bonds between atons breaking of covalently bonded crystals
D.
a gas of nearly free electrons formed by the outer electrons of the metal atoms
【单选题】What is the main idea of the following paragraph? Iron is the most common metal in today's society. It is used in the construction industry, vehicle manufacturing, machinery, cookware, weapons and too...
A.
i Iron is very plentiful
B.
ii Iron is a useful metal
C.
iii Steel beams are made of iron
【单选题】The primary reason for the malleability of metal is?
A.
the nondirectional nature of metallic bonding
B.
the slide ability of planes of atoms in a metal under stress
C.
the bonds between atoms breaking of covalently bonded crystals
D.
a gas of nearly free electrons formed by the outer electrons of the metal atoms
【判断题】Because the total concentration of a polluting element in an environmental sample provides no information concerning the fate of the element in terms of its interaction with sediment, its ability to c...
【单选题】Toughness is ______ ability of a metal to resist, or absorb, sudden shocks of loads without breaking.
【单选题】下列有关温度对酶活性影响的说法,哪一个是正确的? 答( )
A.
①温度从摄氏 80 ° 至 90 ° 升高 10 ° ,通常使反应速度增加 1 倍;
C.
③温度从摄氏 25 ° 升至 35 ° 使具有活化能的反应物分子数增加;
【单选题】有关温度对酶活性影响不正确的是
B.
酶是蛋白质,即使反应的时间很短也不能提高反应温度
【判断题】Because the total concentration of a polluting element in an environmental sample provides no information concerning the fate of the element in terms of its interaction with sediment, its ability to c...