How many neutrons are in an atom with the atomic number of 15 and an atomic mass number of 34?

? 19

? 15

? 34

A person suffering from hyponatremia has a sodium ion concentration in the blood of 0.117 M and a total blood volume of 4.9 L. Part A What mass of sodium chloride would need to be added to the blood to bring the sodium ion concentration up to 0.

Calculate the pH of lemon juice to three significant figures, with a hydrogen ion concentration of 2.12 x 10^-3 mol dm^-3

Determine the volume of a 75-gram sample of gold at stp

Why are isotopes that have relatively short half lives the only ones used in medical diagnostic tests?

What happens to an electron during an electron transition? A. The electron gains mass and falls into the nucleus of the atom. B. The electron flows between continuous energy levels when it gains or loses energy. C.

How is the ocean important to human survival? restate the question

A sample of pure lithium contains 7.99% lithium by mass. What is the % lithium by mass in a sample of pure lithium nitrate that has twice the mass of the first sample?

What ecosystem is being described in the passage?

In the enzyme reaction above, catechol is the substrate, oxygen is a reactant, catechol oxidase is the enzyme, benzoquinone is the product, and water (H2O) is a by-product. Which of the following will decrease the rate of this reaction? a.

How do acids and bases affect the quality of freshwater sources?