This opaque mineral shows a dull, or dully-metallic luster and is typically black or brown-black in color, typically shows no strong cleavage, has a hardness of 5.5 - 6.5 and produces a black streak, has a specific gravity of 5.2, may react weakly with HCl, is strongly magnetic and will attract iron filings. What is this mineral

Which statement is usually true about the relationship between activation energy and reaction rates? low activation energy barriers result in low rates. high activation energy barriers result in low rates. low activation energy barriers result in no reaction. high activation energy barriers result in no reaction.

The yearly amounts of carbon emissions from cars in belgium are normally distributed with a mean of 13.9 gigagrams per year and a standard deviation of 5.8 gigagrams per year. find the probability that the amount of carbon emissions from cars in belgium for a randomly selected year are between 11.5 gigagrams and 14.0 gigagrams per year. a. 0.340 b. 0.660 c. 0.167 d. 0.397

Essay-alternative energy sources research sources of energy that are being developed. write a report of 350-400 words discussing the information you learned concerning the development of various energy sources and the impact that you think they will have on your life. include sources cited at the end of your report using the mla format. follow the rubric guidelines. note that wikipedia is not an appropriate resource for a research paper. worth 99