A 50.0-mL aliquot was taken from a 500.0 mL sample of tonic water containing an unknown amount of quinine and diluted to a volume of 200.0 mL. At 347.5 nm, the fluorescence intensity of the diluted sample was measured as 127 on an arbitrary scale. Under similar conditions, a 25.0 ppm standard quinine solution had a fluorescence intensity of 193.
(a) Calculate the mass of quinine in the original tonic water sample.

0.0329g of quinine

Explanation:

If 25.0ppm of quinine solution had a fluorescence of 193, the solution that had a fluorescence of 127 has as concentration:

127 × (25.0ppm / 193) = 16.45ppm

As the solution was diluted from 50.0mL to 200.0mL, the sample tonic of water contains:

16.45ppm × (200.0mL / 50.0mL) = 65.8 ppm

As the original solution contains 500.0mL, mass of quinine is:

0.5000L × (65.8mg / L) = 32.9mg ≡ 0.0329g of quinine

explanation:

the largest database of organic compounds lists about 10 million substances, which include compounds originating from living organisms and those synthesized by chemists. the number of potential organic compounds has been estimated at 1060—an astronomically high number. the existence of so many organic molecules is a consequence of the ability of carbon atoms to form up to four strong bonds to other carbon atoms, resulting in chains and rings of many different sizes, shapes, and complexities. the simplest organic compounds contain only the elements carbon and hydrogen, and are called hydrocarbons. even though they are composed of only two types of atoms, there is a wide variety of hydrocarbons because they may consist of varying lengths of chains, branched chains, and rings of carbon atoms, or combinations of these structures. in addition, hydrocarbons may differ in the types of carbon-carbon bonds present in their molecules. many hydrocarbons are found in plants, animals, and their fossils; other hydrocarbons have been prepared in the laboratory. we use hydrocarbons every day, mainly as fuels, such as natural gas, acetylene, propane, butane, and the principal components of gasoline, diesel fuel, and heating oil. the familiar plastics polyethylene, polypropylene, and polystyrene are also hydrocarbons. we can distinguish several types of hydrocarbons by differences in the bonding between carbon atoms. this leads to differences in geometries and in the hybridization of the carbon orbitals.

why is cellular respiration important for homeostasis?

it changes food into energy that the organism can use.

which of the following is most likely to happen if a cell is not able to divide?

the cell will not be replaced when it is damaged.

explanation: