. Indoor Sky Diving Facility: The air-handling system for a large vertical wind tunnel used at an indoor sky diving facility has a fan at the inlet located at the bottom, and a test section where the users fly with a circular cross-section of 5.5 m diameter. The designers want to achieve a 200 km/hr air speed in the test section when it is nominally at 22 C and 1.0 bar. (a) What is the mass flow rate of air required by the wind tunnel fan to meet these conditions? (b) If the pressure of the air at the exit of the wind tunnel is 1.5 kPa lower than the pressure in the test section, what is the air velocity at the exit if the air temperature remains at 22 C?

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.

the objects have the same charge is correct.

nathan lee