The melting points of four impure samples of lead(II) bromide were measured. The results are shown.
Which sample is the most pure?
temperature when
the sample started
to melt/ °C
temperature when
the sample finished
melting/°C
А
342
355
B
353
360
С
365
371
D
372
373
А
o

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Select each correct answer. more than one answer may be correct. which of the following is a characteristic of unicellular organisms? they can possess tissues and organs. all of their functions are performed by a single cell. they are usually microscopic. each of their cells is specialized to perform a specific function.

Suppose a lab group reports a ppercent yield of sand of 105. is it really possible to collect more sand than was originally represented? what is the possible explanation for the extra product?