Black for the first,
Brown for the second,
And,
White for the third.
Hope that his helps you..
Answer:
- A, B, C and D are: elements or molecules
- A and B are: reactants
- C and D are: products
Explanation:
The expression "A + B <--> C + D" represents a chemical equation. A chemical equation represents the "mixture" of molecules or elements that will react and form other molecules and elements, so we can say that A, B, C and D represent molecules or elements.
But not only that. In a chemical equation, the elements and molecules that are before the symbol "<-->" represent the reagents in the equation. Therefore, A and B are the reagents. The elements or molecules found after the symbol "<-->" are the products of the reaction. Therefore, C and D are the products.
Answer:
The answer is Endothermic!
Johannes Kepler was the one who elucidated the 3 laws of planetary orbits, the chief one being the elliptical orbits of the planets around the sun with the sun at a focal point at one end of the orbits. This was derived especially from careful observations by Tycho Brahe of the heavens and based on his model of the orbits so was scientifically based.
