What element has 81 protons in the nuclei of its atoms?

A. Platinum

B. Uranium

C. Lead

D. Thallium

How many moles of pcl5 can be produced from 60.0 g of cl2 (and excess p4) ?

Photochemical smog consists of a. coal dust c. ozone b. water droplets and soot d. acid rain

Which is the reason that ionic compounds are brittle?

Predict the products in the following reaction: AgNO3 (aq) + Na2CrO4 (aq) → A. AgCrO4 (s) + Na2NO3 (aq) B. Ag2CrO4 (s) + NaNO3 (aq) C. Ag (CrO4) 2 (s) + Na2NO3 (aq) D. Ag (CrO4) 3 (s) + Na (NO3) 2 (aq)

If 6.0 g of fe (co) 5 reacts with 4.0 g of pf3 and 4.0 g of h2, which is the limiting reagent

What is the volume of 1.9 moles of chlorine gas (Cl2) at standard temperature and pressure (STP) ? 12 L 22.4 L 43 L 81 L

This decomposition is first order with respect to phosphine, and has a half‑life of 35.0 s at 953 K. Calculate the partial pressure of hydrogen gas that is present after 70.5 s if a 2.20 L vessel containing 2.

A new element has two isotopes, one with a mass of 40.0 amu and the other with a mass of 42.0 amu. the atomic weight is 40.50 g/mol. pick the true statement a. the isotope at 42.0 amu is less abundant b. the element has 19 protons and 21 neutrons c.

Which of the following wave is most like visible light? a sound wave moving through the air a radio wave moving through space a water wave moving through a lake a sound wave moving through wood

What holds the atoms together in a covalent bond? the attraction between the shared electrons and protons in each nucleus a weak electron cloud the attraction of the opposing ions the crystal lattice structure