How many moles of cr are in 156 g of the element?
a. 1.0 mol
b. 3.0 mol
c. 6.5 mol
d. 156 mol

Transportation is the largest single source of air pollution in the united states. air pollution can harm the environment and human health. which technology could offer a solution to this problem? mufflers that reduce noise motors that run on electricity tires that improve gas mileage

As air becomes more dense, (select all that apply) o. air weighs less o. gas molecules are closer together o. air is colder o. air weighs more o. gas molecules are further apart o. air is hotter

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.