Naturally occurring copper exists in two isotopic forms: 63cu and 65cu. the atomic mass of copper is 63.55 amu. what is the approximate natural abundance of 63cu?

Imagine that you’re getting ready to move to a new city. when people move, they are influenced by push factors and pull factors, and you have many reasons for your move. which of the following factors is an example of a pull factor? a. wanting to move because you’ve found a great new school somewhere new b. needing to move because there are not enough resources in your old hometown c. being forced to move because your old home is gone d. having to move because there are no jobs in your current hometown

A3.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 ml. then 10.0 ml of this solution was placed in a 50-ml volumetric flask and treated with 5 ml of phenol solution plus 2 ml of sodium hypochlorite solution. the sample was diluted to 50.0 ml, and the absorbance at 625 nm was measured in a 1.00-cm cuvette and found to be 0.486. for reference, a standard solution was prepared from 10.0 mg of nh4cl (molar mass = 53.49 grams/mole) dissolved in 1.00 l of water. then 10.0 ml of this standard was placed in a 50-ml volumetric flask, treated in the same manner as the unknown, and the absorbance found to be 0.323. finally, a reagent blank was prepared using distilled water in place of unknown, it was treated in the same manner as the unknown, and the absorbance found to be 0.076. calculate the weight percent of nitrogen in the protein.

How are evaporation and sublimation similar? a both involve the formation of a gas. b both release energy to the surroundings. c both take place throughout a solid. d both take place at the surface of a liquid.