Which of these is a demonstration of a chemical change?
a. ice melting into water
b. wood becomes charred and black from burning
c. water evaporates from a sugar solution, leaving behind sugar crystals
d. a balloon suddenly popping
explain the answer : )

Given that the molar mass of nano3  is 85.00  g/mol, what mass of nano3  is needed to make 4.50  l of a 1.50  m nano3solution? use  .6.75 g18.9 g255 g574 g

In vapor-liquid equilibrium in a binary mixture, both components are generally present in both phases. how many degrees of freedom are there for such a system? the reaction between nitrogen and hydrogen to form ammonia occurs in the gas phase. how many degrees of freedom are there for this system? steam and coal react at high temperatures to form hydrogen, carbon monoxide, carbon dioxide, and methane. the following reactions have been suggested as being involved in the chemical transformation:

Ahelium balloon contains 16.9 l of helium at stp. how many atoms of helium are in the balloon