Ann is studying acid base neutralization reactions and mixes sodium hydroxide and hydrochloric acid. The reactants were clear, colorless solution and mixing them produces a clear, colorless final solution and the beaker becomes warm. She knows this reaction
forms liquid water and an aqueous salt based on the neutralization rules as shown by the chemical equation. What physical evidence
indicates that there has been a chemical rea
NaOH(aq) + HCl(aq) - NaClaq) + H2 °C)
图 40)
A)
The solution changes color.
B)
Precipitate formation occurs.
C)
The beaker changes temperature.
D)
Gas bubbles form during the reaction.

Long term exposure to waves can cause sunburns and skin cancer. a) visible b) infrared c) gamma rays d) ultraviole

A3.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 ml. then 10.0 ml of this solution was placed in a 50-ml volumetric flask and treated with 5 ml of phenol solution plus 2 ml of sodium hypochlorite solution. the sample was diluted to 50.0 ml, and the absorbance at 625 nm was measured in a 1.00-cm cuvette and found to be 0.486. for reference, a standard solution was prepared from 10.0 mg of nh4cl (molar mass = 53.49 grams/mole) dissolved in 1.00 l of water. then 10.0 ml of this standard was placed in a 50-ml volumetric flask, treated in the same manner as the unknown, and the absorbance found to be 0.323. finally, a reagent blank was prepared using distilled water in place of unknown, it was treated in the same manner as the unknown, and the absorbance found to be 0.076. calculate the weight percent of nitrogen in the protein.

What effect might melting sea ice have for people who live in coastal areas?