9. When a piece of steel wool is burned it gains mass. Which explanation is consistent with the law of conservation of mass? A. Matter was created during the chemical reaction,
B. Heat changed into matter.
C. Matter from the air combined with the steel wool.
D. A chemical change did not take place.

Layers of rock containing fossils, like the layers illustrated here, are most likely composed of rocks.

What woukd most likely be the transmittance at a 0.70 m solution of solute a? a) 7.6%b) 1.1%c)4.0%d)4.6%

Achemistry student needs to standardize a fresh solution of sodium hydroxide. he carefully weighs out of oxalic acid , a diprotic acid that can be purchased inexpensively in high purity, and dissolves it in of distilled water. the student then titrates the oxalic acid solution with his sodium hydroxide solution. when the titration reaches the equivalence point, the student finds he has used of sodium hydroxide solution.calculate the molarity of the student's sodium hydroxide solution. be sure your answer has the correct number of significant digits.