Which of the following statements is true?

Sound vibrations are changed into electrical impulses by the eardrum.
It is dangerous to listen to sounds over 160 dBs.
High-pitched sounds have low frequencies.
All of the above.

Which compound contains both ionic and covalent bonds? a) hbr b)cbr4 c)nabr d) naoh

Pegmatites are igneous rocks in which the individual minerals are very large. typically, the minerals are all light-colored quartz, feldspar and muscovite. if you were given a black and white photograph of a pegmatite in a quarry (where the rock has been blasted and broken), what physical properties could you use to identify those three minerals in this hypothetical photo? describe each mineral and the specific diagnostic properties. be specific.

You have a sample of a metal, the sample is exactly 6.02 x 1023atom, if the sample has a mass 55.85 what metal is your sample made of?