Answer:
A
Explanation:
because they have delocalized electrons
Explanation:
rain, snow, cloud, fog or dry deposition - Dry particles, or gas
Answer:
A. To be precise, it must be able to make measurements repeatedly over a long period of time.
Explanation:
The precision of a scientific measuring tool can be defined as how close the values between multiple measurements are to each other, when repeated under the same conditions.
This ultimately implies that, the precision of a scientific measuring tool reflects the reproducibility and repeatability of its measurements, irrespective of how accurate the measurements are.
In science, one of the most effective ways to determine the precision of a scientific measuring tool is to find the difference between the highest and lowest measurements (measured values).
Hence, the statement which correctly describes a characteristic that a scientific measuring tool should have is that, to be precise, it must be able to make measurements repeatedly over a long period of time.
Answer: caffeine is a compound.
Explanation:
1) As stated c<span>affeine contains hydrogen, carbon, nitrogen, and oxygen atoms in a fixed ratio.
2) The definition of compound is a pure substance formed by chemical bonding of two or more fifferent elements. That means a defined ratio of the elements in the compound, which conferes uniform and equal properties to every part of the compound.
Some examples of compounds are salt (NaCl), water (H2O), vinegard (CH3 COOH).
A mixture combines several elements or compounds, not bonded by chemical bonds but mixed in ratios which may vary.
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