Sodium nitrite ion is a preservative used in the curing of meat, but is potentially carcinogenic. nitrite concentrations are commonly determined using the griess reaction. in this reaction, the sample containing nitrite is reacted with sulfanilamide and n-(1-naphthyl)ethylenediamine to form a colored species that absorbs at 550 nm. 50.0 ml of a food extract known to contain no nitrite had a percent transmittance of 78.35%. 50.0 ml of a food extract with a known concentration of 1.25  10–5 m no2 –had a percent transmittance of 9.38%. 50.0 ml of a food extract with an unknown amount of nitrite had a percent transmittance of 18.84%. how many micrograms of nitrite, no2 – (fm: 46.01 g/mol), are present in the 50.0 ml of food extract containing an unknown amount of nitrite?

What is driving behind plate tectonics (plate movment)? a) gravity only b) inertia c) convection and gravity d) the sun theres no option for science so i picked chemistry. plz

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

Straightforward questions answered in the powerpoint slidesreaction: heating the starting materials under refluxwhat does it mean to heat under reflux? why do we choose water as the reflux solvent? what are boiling chips used for? why do we put a condenser on top of the reaction? why do we add heat and let the reaction stir for 30 minutes? why do we add sulfuric acid to the reaction after it cools as opposed to when it’s still hot? separation: filtration of precipitatewhy don’t we do an aqueous and organic extraction in the separatory funnel? why do you rinse the salicylic acid on the filter with ice cold water? purification: recrystallization of salicylic acid (no hot filtration needed)what is the difference in the amount of room temperature water vs. boiling water needed to dissolve the salicylic acid (assume a 1.2 gram yield of salicylic acid)? remember, in the lab if you need x ml of boiling water to dissolve a solid, then you should add a little more (definitely no more than 1.5 times the theoretical amount) to ensure it doesn’t recrystallize prematurely. analysis: melting point of salicylic acidwhat can you conclude if the melting point of the salicylic acid you just synthesized is 152-155oc and the 1: 1 mix of your product and “synthetic” salicylic acid is 151-154oc?