HELP ITS URGENT thanks if u do

1. A homogenous mixture is a mixture that appears as a single-phase or, in other words, the parts of the mixture are not distinguishable.  A heterogeneous mixture appears as two or more components that are distinguishable from each other.

a. E

b. O

c. O

d. E

e. O

f. E

2.  Molecules are made up of atoms (building blocks). Atoms consist of protons, neutrons, and electrons. Atoms cannot be separated by chemical reactions while molecules can be separated by chemical reactions.

3. A pure substance is chemically bonded together and can only be separated through chemical processes. A homogenous mixture, however, is not chemically bonded and can be separated through physical methods.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.