Which compound are ionic and which are covalent? (n2) (ccl4) (sio2) (alcl3) (cacl2) (libr)

The wave shown on the electromagnetic spectrum disturb the medium it passes through a)different frequency. b)the same frequency .

Flourine is found to undergo 10% radioactivity decay in 366 minutes determine its halflife

100 grams of molten lead (600°c) is used to make musket balls. if the lead shot is allowed to cool to room temperature (21°c), what is the change in entropy (in j/k) of the lead? (for the specific heat of molten and solid lead use 1.29 j/g⋅°c; the latent heat of fusion and the melting point of lead are 2.45 × 104 j/kg and 327°c, respectively.)