One atmosphere is numerically equal to approximately

Choose the correct statements.
$A$. Weight of a substance is the amount of matter present in it.
$B$. Mass is the force exerted by gravity on an object.
$C$. Volume is the amount of space occupied by a substance.
$D$. Temperatures below $0^{\circ} C$ are possible in Celsius scale,but in Kelvin scale negative temperature is not possible.
$E$. Precision refers to the closeness of various measurements for the same quantity.

$0.1 \, mol \, L^{-1}$ means how much $mol \, m^{-3}$ and how much $mol \, cm^{-3}$?

The number of significant figures in $50000.020 \times 10^{-3}$ is ..... .

Given the numbers: $161 \ cm, 0.161 \ cm, 0.0161 \ cm$. The number of significant figures for the three numbers are

One calorie is equal to (in $J$)