What kind of chemical reaction these equations represent. S+Cl2=SCl2
2C2H2+5O2=4CO2+2H2O
CH4=C+2H2

List four observations that indicate that a chemical reaction may be taking place

Which of the following would be an accurate picture of the earth during the summer time of the northern hemisphere?

A2.5% (by mass) solution concentration signifies that there is a 2.5 % (by mass) solution concentration signifies that there is blank of solute in every 100 g of solution. of solute in every 100 g of solution