If a substance is not able to be separated by physical means but is able to be separated by chemical means, it is a(n)
solution
heterogenous mixture
element
compund

Why do scientists look for patterns in the world? a. patterns can explain observations. b. patterns never change, no matter what. c. patterns are easy for scientists to detect. d. patterns are all the same, through all time.

How many grams of oxygen gas are contained in a 15 l sample at 1.02 atm and 28°c? show your work.

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?