The gas that cannot be collected over water is

$A$ ball is let fall from a height $h_0$. It makes $n$ collisions with the earth. After $n$ collisions it rebounds with a velocity $v_n$ and the ball rises to a height $h_n$. Then the coefficient of restitution is given by:

Most of the endangered species are the victims of

In an astronomical telescope in normal adjustment,a straight black line of length $L$ is drawn on the inside part of the objective lens. The eyepiece forms a real image of this line. The length of this image is $I$. The magnification of the telescope is:

The heat evolved in the combustion of methane is given by the following equation:
$CH_{4(g)} + 2O_{2(g)} \to CO_{2(g)} + 2H_2O_{(l)};$
$\Delta H = -890.3 \, kJ$
How many grams of methane would be required to produce $445.15 \, kJ$ of heat of combustion?

Opium is obtained from the latex of the unripe fruit of which plant?