Elements can combine to form molecules, like o2 or co2. elements combine to form molecules and these elements are joined together by chemical bonds i.e covalent bond in this molecule so option A is correct
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Answer:
By using any one technique like boiling, distillation, condensation ,etc , one can be used to distinguish between a pure substance and a homogeneous mixture.
Explanation:
If the liquid is a pure substance, then it can not be separated by using physical means because all atoms of a pure substance show same properties.
But on the other hand, if there is homogeneous mixture, it can be separated by using techniques like boiling, distillation, condensation ,etc.
<u>Thus, using any of the one method listed above can be used to distinguish between a pure substance and a homogeneous mixture.</u>
Parsec is a unit of distance (as stated 1 Parsec = 3.26 light years, wihch is 3.26 times the distance run by light in one year).
That distance is:
1 parsec = 3.26 mi× 186,000 mi/s × 3600 s/h × 24 h/day × 365 day/ year × 1 year = 19,122,168,960,000.mi.
So, the question of <span>how many parsecs it takes for light to reach Mars from Earth does not make sense because parsecs is not a unit of time.
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</span><span>You can calculate how many parsecs is equivalent to the distance between Mars and Earth, 60,000,000 km. For this you can first calculate the equivalence of which you do in this way:
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</span><span>60,000,000 km × 0,621 mi/km × 1 parsec / ( 19,122,168,960,000 mi) = 1.94E-6 parsecs.
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Answer:
1st one is correct, Igneous rocks are formed when molten rock cools and hardens.