Which of the following is not a potential sign of a chemical change?
a) release of gas
b)evaporation of water
c)change of color
d) production of gas

1) which of the following is the best example of a physical change? a) sugar dissolving in tea b) firefly glowing 2) in the combustion of ethane, what is/are the reactants? c2h6 + o2 ==> co2 + h2o a) c2h6 and o2 b) co2 and c2h6

Why is retrograde motion an apparent motion

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit