Identify the following as an element or compound. Copper(ll) oxide(CuO)
Please help I have no clue what I'm doing

If 1.63 times 10 negative 4 of helium dissolves in 100.0g of water, what is the concentration in parts per million

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?

A100 kmol/h stream that is 97 mole% carbon tetrachloride (ccl4) and 3% carbon disulfide (cs2) is to be recovered from the bottom of a distillation column. the feed to the column is 16 mole% cs2 and 84% ccl4, and 2% of the ccl4 entering the column is contained in the overhead stream leaving the top of the column. calculate the mass and mole fractions of ccl4 in the overhead stream, and determine the molar flow rates of ccl4 and cs2 in the overhead and feed streams. 12. mw_ccla- 153.82; mw_cs2-76.14.