A student uses visible spectrophotometry to determine the concentration of CoCl2(aq) in a sample solution. First the student prepares a set of CoCl2(aq) solutions of known concentration. Then the student uses a spectrophotometer to determine the absorbance of each of the standard solutions at a wavelength of 510nm and constructs a standard curve. Finally, the student determines the absorbance of the sample of unknown concentration. A wavelength of 510nm corresponds to an approximate frequency of 6×1014s−1. What is the approximate energy of one photon of this light?

9×1047J
3×1017J
5×10−7J
4×10−19J

The valve seat performs two functions: it provides a seal for the valve in the combustion chamber, and it provides a cool surface to carry heat away from the valve. most valves use a seating angle.

Rewrite the following sentences in active voice. caution: one sentence (only one) is written in active voice. do not rewrite it just label it as being active. 1). the use of copernicus's theory was forbidden by religious leaders until 1757. 2). i am puzzled by your question. 3). the girl is frightened by horror movies; she only watches chick-flicks. 4). radium and polonium were discovered by marie curie. 5. most of the town was destroyed by a tornado. 6). these flowers were planted by the 4-h club. 7). the little boy showed his mother the bruises, cuts. and bumps on his shin. 8). pluto was discovered by clyde william tombaugh in 1930 in flagstaff, arizona. 9). the painting was purchased by mr. jones. 10). the song was performed many times by kate smith. 11). england was ruled by a woman nicknamed "bloody mary" from 1553-1558. 12). the law of universal gravitation was discovered by sir isaac newton.

Many people have a negative opinion of classical music because they subscribe to common myths about this type of music. true false