A sample of lead is found to contain three isotopes: 23.5% of the sample has a mass of 204 amu, 24.1% has a mass of 207 amu, and the remainder has a mass of 208 amu. What
is the average atomic mass of lead?
0 206.3 amu
207.2 amu
O 82.0 amu
0 206.8 amu

Apeak with a retention time of 407 s has a width at half-height (w1/2) of 7.6 s. a neighboring peak is eluted 17 s later with a w1/2 of 9.4 s. a compound that is known not to be retained was eluted in 2.5 s. the peaks are not baseline resolved. how many theoretical plates would be needed to achieve a resolution of 1.5?

Which element is the least metallic between cadmium, silver, zinc, or iron?

Suppose you wanted to make 100 grams of water. what is the molar mass of water (h2o)?