Naturally occurring copper is 69.15% copper-63 (atomic mass = 62.93 amu) and 30.85% of some other isotopic form of copper. What must the atomic mass of this second isotope be in order to account for the 63.55 amu average atomic mass of copper? (Write the answer to two decimal places.)

64.94 First, write out an expression about what we know 0.6915 * 62.93 + 0.3085 * x = 63.55 Now solve for x 0.6915 * 62.93 + 0.3085 * x = 63.55 43.5161 + 0.3085 * x = 63.55 0.3085 * x = 20.03391 x = 64.93972 Rounding the answer to 2 decimal places gives x = 64.94.

can you attach a picture of the lettuce? : )

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.