An isotope of yttrium has 39 protons and 59 neutrons. what is the atomic mass of that isotope?

given the equation Mg + 2HCL - -> MgCL2+H2, how many moles of hydrochloric acid are needed to react with O. 50 mole of magnesium?

If I have 6.02 x 10^23 atoms of silicon, how many grams of silicon do I have?

16) How many photons are contained in a burst of yellow light (589 nm) from a sodium lamp that contains 609 kJ of energy? A) 3.37 * 1019 photons B) 3.06 * 1030 photons C) 1.81 * 1024 photons D) 4.03 * 1028 photons E) 2.48 * 1025 photons

Which of the forces of molecular attraction is the weakest?

Which substance has a chemical formula with the same ratio of metal ions to nonmetal ions as in potassium sulfide? (1) sodium oxide (2) sodium chloride (3) magnesium oxide (4) magnesium chloride

Which exerts greater pressure on the floor-standing flat-footed or standing on tiptoe? on tiptoe, because the force acts over less area on tiptoe, because the force acts over more area flat-footed, because the force acts over more area flat-footed,

1. Sara tells Michael she is 160 centimeters tall, while Michael says he is 60 inches tall. If there are 2.54 centimeters in an inch, who is taller

How do you tell if a compound is polar or non polar

What two ions are central to the arrhenius definitions of acids and bases?

Question 1 A process in which suthetances chemically rearrange to form new substances o Molecule Energy o Organism O Chemical reaction O Matter O Cellular respiration