Are physical properties only observable by destroying the substance?

Form which sphere does most water evaporate? A:hydrosphere B:biosphere C:atmosphere D:lithosphere

For main-group elements using the older numbering system the group number on the periodic table corresponds to which characteristic of the elements of that group

Why does a drop of water form a sphere

Are phase changes physical or chemical changes? why?

Which statement is true if the Delta. Hrxn of a reaction is positive? The reaction is endothermic. The reaction is exothermic. There is more reactant than product. There is more product than reactant.

Assume 3 molecules of Fe react according to the following equation. 3Fe + 4H2O Fe3O4 + 4H2 How many molecules of H2 are produced? How many water molecules are required? What is the mole ratio of Fe to H2O?

10.0 mL of a HF solution was titrated with a 0.120 N solution of KOH; 29.6 mL of KOH were required to completely neutralize the HF. Calculate the normality of the HF solution.

The number of grams present in 1.35 mol of Fe is

Which can associate a suspect's gun with a crime?

In which era did the first fish appear? a. Carboniferous b. Paleozoic C. Mesozoic d. Permian