The difference between a physical and a chemical change is: 1.physical change changes the phase of matter
2.chemical change changes the phase of matter
3.physical change includes phase change of matter
4.chemical change changes composition of matter

Asample of the male sex hormone testosterone, c19h28o2, contains 3.88×10^21 atoms of hydrogen.(a) how many atoms of carbon does it contain? (b) how many molecules of testosterone does it contain? (c) how many moles of testosterone does it contain? (d) what is the mass of this sample in grams?

What is the importance of interlocking the fingers and rubbing while washing hands? the palms are the dirtiest parts of the hands. the spaces between the fingers get washed. the backs of the hands get washed. the fingernails are the dirtiest parts of the hands

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