People who stop a they had been using habitually can experience symptoms such as fatigue and trouble sleeping. What is this called? A. withdrawal b. addiction c. physical dependence d. psychological dependence

Acompound is found to contain 6.1% hydrogen and 93.9% oxygen. find it’s empirical formula.

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?

Evaluate this exponential expression,8. (2 + 3)2 – 42