Which element has the greatest density at STP?

(1) magnesium (3) barium

(2) beryllium (4) radium

Now consider the time to begin at 2.3 min, where [H2O2] = 0.50 M. How much time is required to cut the concentration in half again, in this case from 0.50 M to 0.25 M?

F an atom gains 2 electrons, what is the charge on the resulting ion? b. give an example.

An electron is on a - 2.5 eV energy level. the electron is stuck by a 2.5 eV photon. What will most likely happen?

The combustion of ethane ( C 2 H 6 ) produces carbon dioxide and steam. 2 C 2 H 6 ( g ) + 7 O 2 ( g ) ⟶ 4 CO 2 ( g ) + 6 H 2 O ( g ) How many moles of CO 2 are produced when 5.05 mol of ethane is burned in an excess of oxygen?

Find volume of 1 mole of helium gas when the pressure is 1.46 atm and the temperature is 270k

Carbon dioxide, or CO2, is a (n) A.) atom. B.) mixture. C.) element. D.) compound.

If the atomic number of an element is 6 and its mass number is 20, how many neutrons are in the atom's nucleus?

A chemist exploring potential fuels for use in outer space is considering using vaporized aluminum chloride as a fuel.

Dinitrogen monoxide has a structural formula of NNO and requires resonance structures in order to draw the Lewis structures of the molecule.

Mg + 2HCI >MgCI2 + H2 What is the answer of the chemical reaction?