She is a girl. ______ name is Joy. [ ]
A. My
B. Her
C. She
D. His
答案:B
下列各组溶液中,c(Cl-)最大的是( )
A.500mL1mol/LKCl
B.800mL0.5mol/LMgCl2
C.250mL1mol/LFeCl3
D.200mL1mol/LCaCl2
质量为900g的物体静止在水平地面上,受到的重力为多少N?(g=10N/kg)