Which element is a metalloid out of aluminum, arsenic, carbon, and helium?

If i make a solution by adding 83grams of sodium hydroxide to 750ml i’d water what is the molarity of sodium hydroxide

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

What human activity increases beach erosion?