Answer:
a solution color becoming less intense due to dilution- is not an evidence of a chemical reaction
bubbles (gas formation) - evidence of a chemical reaction
explosion or fire - evidence of a chemical reaction
changes in color- evidence of a chemical reaction
precipitation- evidence of a chemical reaction
changes in temperature - evidence of a chemical reaction
a solid liquifying - is not an evidence of a chemical reaction
solution colors mixing - is not an evidence of a chemical reaction
Explanation:
A chemical change is not easily reversible and yields new substances. It is often accompanied by a loss or gain of heat.
In the answer section, i have shown some evidences that lead us to conclude that a chemical reaction has taken place. The occurrence of a chemical change often goes with the formation of new substances as earlier stated and any of these signs may accompany the process.
For instance, when a metal is dropped in dilute acid solution, bubble of hydrogen gas indicates that a chemical reaction has taken place.
Answer:
An Educated Guess
Explanation:
After the scientist is done with the experiment he should do an educated guess, they use the data from the experiments to make charts and graphs to communicate the results of the experiment. After the scientists makes the hypothesis, they perform this procedure.
Answer:
4
Explanation:
Avogadro’s number represent the number of the constituent particles which are present in one mole of the substance. It is named after scientist Amedeo Avogadro and is denoted by 
.
Also, it is the number of particles in exactly 12.000 g of isotope carbon 12.
Avogadro constant:-
Hence,
Mass of 
= 131.293+ n18.998 g
So,
molecules have a mass of 131.293+ n18.998 g
Also,
molecules have a mass of 
g
So,
molecules have a mass of 
g
Also, given mass = 0.172 g
Thus,
<u>Thus, value of n is 4.</u>
Answer:
They agree to ethical standards when they are licensed.
Explanation:
