What does it mean when substance are move against a concentration gradient?

A certain radioactive material has a half-life of 36 minutes. Starting with 10.00 grams of this material, how many grams will be left after 2 hours? A) 1.00 grams B) 1.5 * 10-4 grams C) 3.33 grams D) 0.25 gram

True or false. like poles of magnet attract each other while unlike poles repel each other.

What is the charge of an electron A. - 1 B. 0 C. + 1 D. + 2

Drug abuse will not lead to physical and psychological dependence. True or False?

If, as a pioneer, you wished to warm your room by taking an object heated on top of a pot-bellied stove to it, which of the following 15-pound objects, each heated to 100°C, would be the best choice?

A mixture of two compounds, a and b, was separated by extraction. after the compounds were dried, their masses were found to be: 105 mg of compound a and 91 mg of compound b. both compounds were recrystallized and weighed again.

What are the five types of chemical reactions?

Which chemical reaction do plants use to take carbon dioxide out of the air

What are the primary elements of the earths layres?

How long does it usually take fir a rock to undergo a stage within the rock cycle