How many grams are in 5.8 x 10^25 molecules of Pentanitrogen Dioxide N5O2?

Asample of radium-226 will decay 1/4 of its original amount after 3200years. what is the half-life of radium-226?

If a 12-v battery is connected to a circuit that has a current of 3.0 a, what is the total resistance in the circuit? 36 ohms 4 ohms 0.25 ohms

He table below gives the atomic mass and relative abundance values for the three isotopes of element m. relative abundance (%) atomic mass (amu) 78.99 23.9850 10.00 24.9858 11.01 25.9826 what is the average atomic mass (in amu) of element m? 2.86 5.36 24.30 24.98