Galium has a weighted average atomic mass of 69.7 and two naturally occurring isotopes: gallium-69 and gallium-71. gallium-69 has a relative abundance of 60.1% and a mass of 68.9. the relative abundance of gallium-71 is 39.9%. based on the information, what is the mass of gallium-71?

How can you use chemical equations to predict the products of the reaction you can carry out?

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

Calculate - analysis of compound composed of iron and oxygen yields 174.86 of fe and 75.14g of o. what is the empirical formula for this compound?