A | B | C | D |
澄清石灰水变浑浊,证明蜡烛中含有碳元素 | 蘸酚酞试液的纸条变红,因为分子在不断运动 | 铁粉在氧气中燃烧的现象为剧烈燃烧,火星四射,放热,生成四氧化三铁 | 红墨水变无色,因为活性炭具有吸附性 |
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