Which type of property cannot be seen just by observing with the senses

Write the formula for the following chemicals. 7. e. trinitrogen tetraoxide a calcium phosphate f. magnesium acetate b. potassium sulfide g nickel(iii) cyanide c carbon dioxide h. silver sulfate d. cobalt(ii) chloride

When a septic tank backs up a goes in to clean it out

An atom of which element reacts with an atom of hydrogen to form a bond with the greatest degree of polarity ?