2)As figuras a seguir constituem os sistemas fechados nós quais as bolinhas representam átomos. Classifique os sistemas I II III IV em substância composta ou mistura . I: II: III: IV: me ajuda prf​

There are 6.022 x 10^23 atoms of hg in 1 mole of hg. the number of atoms in 4.5 moles of hg can be found by multiplying 4.5 by 6.022 x 10^23 a. 2.7 x 10^24 b. 27 x 10^23 c. 2.71 x10^24 d. 27.099 x 10^23

The covalent compound acetylene, which is the fuel of the oxyacetylene torch used by welders, has the molecular formula c2h2. the covalent compound benzene, a commercial solvent, has the molecular formula c6h6 each of these covalent compounds contains carbon and hydrogen atoms in a one-to-one ratio. would it be correct to write the chemical formulas of each as ch? explain.

What is the ph of a 0.0010 m hno3? 1.0 3.0 4.0 5.0