实验目的 | 实验设计 | |
A | 鉴别真金和假金(铜锌合金) | 加入稀硫酸 |
B | 检验二氧化碳中混有少量氧气 | 将带火星的木条伸入气体中 |
C | 除去CO2中混有的少量CO | 将气体通过灼热氧化铜粉末 |
D | 除去NaCl溶液中少量的Na2SO4 | 加入适量的BaCl2溶液后过滤 |
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