【单选题】Linda spends her entire budget and consumes 15 units of x and 19 units of y. The price of x is twice the price of y. Her income doubles and the price of y doubles, but the price of x stays the same. I...
【单选题】下列4组组成不同的混合溶液,当Pb(s)插入各组溶液时,金属Sn有可能被置换出来的是(已知 φ Θ (Sn 2+ ,Sn)=-0.136V; φ Θ (Pb 2+ ,Pb)=-0.126V)
A.
a(Sn 2+ )=1.0,a(Pb 2+ )=1.0
B.
a(Sn 2+ )=0.1,a(Pb 2+ )=1.0
C.
a(Sn 2+ )=1.0,a(Pb 2+ )=0.1
D.
a(Sn 2+ )=0.5,a(Pb 2+ )=0.5
【单选题】已知3x 2 ﹣2y+5=7,则9x 2 ﹣6y﹣3=( ) [ ]
【单选题】下列 4 组组成不同的混合溶液,当 Pb(s) 插入各组溶液时,金属 Sn 有可能被置换出来的是 ( 已知 Ф 0 (Sn 2+ , Sn)=-0.136V, Ф 0 (Pb 2+ , Pb) = - 0.126V
A.
a(Sn 2+ )=1.0 , a(Pb 2+ ) = 1.0
B.
a(Sn 2+ )=0.1,a(Pb 2+ )=1.0
C.
a(Sn 2+ ) = l.0 , a(Pb 2+ )=0.1
D.
a(Sn 2+ )=0.5,a(Pb 2+ )=0.5
【单选题】三角形螺纹的牙型角α=_______,而梯形螺纹的牙型角α=_______
【简答题】阅读理解。 Linda Brown works for a big company. Her job is very important, so she has to work a lot-often 60 or 70 hours a week. Linda doesn't like to rest. She never takes vacations. In the morning, after...