22. Ayesha is the technician preparing the spiked samples and performing the analysis. For the spiked sample, she calculates the concentration of in spiked sample to be 27.1 mg/L and she knows that she spiked a concentration of 20 mg/L. If the calculated % recovery is calculated to be 112%, then what was the analyte concentration in the unspiked sample

Matter- occupies space and possesses rest massno matter is the opposite

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant. 

Answer(d) unstable compounds that convert to acetals in the presence of alcohol and an acid; (b) semiacetals produced by alcohol subtraction from ketone;