1) A student is investigating various types of matter based on a simplified
model created in science class. The student examines the salad
dressing bottle, noticing that the oily component and the vinegar
component have separated. The herbs are also distinctly visible in the
oil layer. How would the model help the student determine the
classification of matter for the salad dressing?
If the oily layer can be physically removed from the
vinegar, it must be a mixture. If the herbs can be
physically removed, it must be a solution.
If the oily layer can be physically removed from the
vinegar, it must be a pure substance. If the herbs can
be physically removed, it must be elemental.
B)
C)
If the oily layer can be physically removed from the
vinegar, it must be a pure substance. If the herbs can
be physically removed, it must be a compound.
D)
If the oily layer can be physically removed from the
vinegar, it must be a mixture. If the herbs can be
visibly seen in the midst of the dressing, it must be a
suspension

Comedians like to joke that the reason we haven’t been visited by intelligent life from elsewhere in the universe is that aliens have been monitoring earth’s broadcasts of intellectually embarrassing tv programs, like gilligan’s island, fear factor, the jersey shore, and the jerry springer showand so consider us far too primitive to merit a visit. let’s check the assertion that aliens could have been receiving them. tv programs are broadcast at a frequency of about 100mhz with about 100kw of total power in 30frames per second, which emanatesroughly uniformly in all directions. assume that interstellar space transmits these broadcasts without attenuation. no matter how smart they are, aliens would require at least one photon per frame to interpret our signals. findthe number of photons per unit time per unit area reaching a receiver on a possible planet in the nearest star system, which is about 4 light-years away (a light-year is the distance light travels in a year). if aliens aimed a receiver or detector directly at earth, how big (in diameter) would it have to be to receive a photon per frame

Sobre transformações cíclicas, são feitas algumas afirmações, determine quais estão corretas. i – a variação de energia interna em uma transformação cíclica é nula; ii – o trabalho, em uma transformação cíclica, é sempre positivo; iii – ao completar um ciclo, o gás tem a mesma temperatura com a qual começou a transformação; iv – uma transformação cíclica é, obrigatoriamente, composta de transformações conhecidas, como adiabática, isocórica, etc: a) i e iii b) i e ii c) ii e iii d) i e iv e) iii e iv

Suppose astronomers built a 140-meter telescope. how much greater would its light-collecting area be than that of the 10-meter keck telescope? express your answer using two sign