If an atom has 34 protons and 40 neutrons, what is its mass number?

21% of oxygen in air with barometric pressure of 625. what's partial pressure

One of the essential minerals in the human body is salt. How much salt (NaCl) is in the average adult human body? A. 1 kilogram B. 500 grams C. 250 grams D. Practically none

Calculate the heat change in calories for condensation of 20.0 g of steam at 100∘C.

3. How does adding neutrons affect isotope symbols?

How is a gas different from a solid or a liquid? (choose all that apply)

Which is the MOST accurate description about how the different types of feedback mechanisms work

Which of the following equations violates the law of conservation of mass? A) 2Al + 6HCl yields 2AlCl3 + 3H2 B) Na2C2O4 + Pb (NO3) 2 yields PbC2O4 + 2NaNO3 C) AgNO3 + LiCl yields AgCl + LiNO3 D) 3Ca + 2Cr (NO3) 3 yields 3Ca (NO3) 3 + 2Cr

Which of the following is a true statement about energy? a. energy can be created and destroyed. b. energy is never created nor destroyed. c. energy is easily created, but cannot be destroyed. d. energy cannot be converted from one form to another.

What does a reaction rate tell you

Which phrase provides the best definition of mass movement