Which of the following are exact numbers? (Check all that apply.) 1000 meters in one kilometer.
The diameter of a coin, 10.2756mm (millimeters)
A dozen eggs.
16 ounces in 1 pound.
The length of a pen, 12mm (millimeters)

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?

When 225mg of anthracene, c14h10(s), was burned in a bomb calorimeter the temperature rose by 1.75k. calculate the calorimeter constant. by how much will the temperature rise when 125mg of phenol, c6h5oh(s), is burned in the calorimeter under the same conditions? (δch< (c14h10,s)=–7061 kj mol−1.)

Mary is conducting an experiment on how pollution affects plant growth. how can she ensure that her data are reliable?