You are given a sample containing 0.70 moles of a substance. how many molecules are present in the sample of the substance is benzene c6h6

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Which of the following is a physical property flammability heat of combustion solubility and toxicity

In a ball-and-stick molecular model, what do the sticks represent?