Answer:
In a chemical reaction, there is a change in the composition of the substances; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition.
Explanation:
Answer:
D. Atoms are like solid balls
Explanation:
John Dalton proposed that all matter is composed of very small things which he called atoms. This was not a completely new concept as the ancient Greeks (notably Democritus) had proposed that all matter is composed of small, indivisible (cannot be divided) objects. When Dalton proposed his model electrons and the nucleus were unknown.
It's called a compound because different elements are held together by a chemical bond.
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❖ In order to keep the bench from conducting heat, Shane could build it out of wood. Wood doesn't conduct heat so this would work best for Shane.
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Answer: when reactants and products are gases at STP.
Justification:
1) STP stands for standard temperature (0°) and pressure (1 atm).
2) According to the kinetic molecular theory of the gases, and as per Avogadro's principle, equal volumes of gases, at the same temperature and pressure, have the same number of molecules.
3) Since the coefficients in a balanced chemical equation represent number of moles, when reactants and products are gases at the same temperature and pressure, the mole ratios are the same that the volume ratios, and then the coefficients of the chemical equation represent the volume ratios.