One twelfth the mass of a carbon-12 atom is used to define a (an)

a. atomic mass.

b. mass number.

c. atomic number.

d. atomic mass unit.

How many moles of hydrogen are evolved when an excess of sodium metal is added to one mole of citric acid?

Which is the correct chemical formula for hydrogen gas? A. H2O B. OH C. H3 D. H2

Indicate the coordination number for the central metal atom in each of the following coordination compounds: (a) [Pt (H2O) 2Br2] (b) [Pt (NH3) (py) (Cl) (Br) ] (py =

Suppose a hydrogen atom is in the n = 4 excited state. what is the largest number of photons that can be emitted as the atom returns to the ground state?

Which of these statements explains the relationship among elements, compounds, and mixtures? A. Elements are made of compounds and mixtures. B. Both compounds and mixtures are made up of elements. C.

What physical property is changed when a waitress pours coffee from a pot into four mugs? temperature density volume color

Calcule o calor especifico do estanho sabendo que foram necessarias 100 cal para elevar em 20ºC a temperatura de 100 g de estanho

What's the smallest part of a compound

The inertness of the noble gases is due to a. the outermost shell has six electrons. b. the bonds they form with other elements. c. the number of protons and neutrons. d.

Xander is gaining weight. Which best describes what he can do to prevent obesity? exercise every day and also make healthy choices in his diet excercise once a week but make no change in his diet exercise once a week and also make healthy choices in