目的 | 实验操作 | |
A | 区分软水与硬水 | 取等量硬水、软水,分别滴加等量的肥皂水,振荡 |
B | 区分稀硫酸与氢氧化钠 | 分别用玻璃棒蘸取溶液,滴在pH试纸上 |
C | 区分羊毛与涤纶 | 分别取样,灼烧 |
D | 区分CO2和N2两种气体 | 分别向盛有气体的集气瓶中伸入燃着木条 |
A.A | B.B | C.C | D.D |

同类型试题

y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2


y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2

