A 0.45g sample of mineral ore is analyzed for chromium and found to contain 0.560mg Cr2O4. Express the concentration of Cr2O3 in sample as a. Percent
b. Parts per thousand
c. Parts per million
d. Parts per billion

2. what two items do autotrophs take from the environment to produce their food? 3. what are the two items that are released during transpiration from leaves? 4. what are the two membranes of the system? a.what are the two stages of photosynthesis? what are the two parts of photosynthesis?

4al + 3o2 → 2al2o3 what does the "3" in front of o2 stand for? a) it indicates that there are 5 oxygen atoms after you add the coefficient and the subscript. b) it indicates that that there are are total of 6 oxygen atoms all bonded together as a single molecule. c) it indicates that there are 3 oxygen molecules chemically bonded to each other in the reaction. d) it indicates that there are 3 separate oxygen molecules in the reaction.

Why hydrochloric acid neutralized first when you titrate a mixture of hcl& ch3cooh against standard sodium hydroxide