The results of Dominic and Eva's experiment is unreliable and can lead to a pseudoscientific claim primarily because they did not repeat their tests multiple times. Although, they used the same type of stopwatch in recording the time it takes for the chemical reaction to occur, they have different reactions times. Thus, it would have been better if they conducted several trials then obtained the average of their results.
Answer:
B. Gravity held the pieces of forming planets together.
c. Gravity pulled most of the matter into the center of the solar system
D. Gravity caused the planets and Sun to have spherical shapes.
Explanation:
When a collection of grains pulled together by their gravitational forces would keep in by the gravity of a star, it would eventually became bigger to the point a planet was formed.
The sun's strong gravitational force pulled most of the matter around it to the center of the solar system.
The spherical shape of planets is a result of their gravity pulling equally from all sides, shaping it into a sphere.
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.
The given compound is Aluminum sulfate, Al2(SO4)3:
Molar masses:
Aluminum = 27 g/mol
Sulfur = 32 g/mol
Oxygen = 16 g/mol
The total molar mass is 342 g/mol
The ratio by mass of the elements:
Aluminum = 27*2/342
= 0.16
Sulfur = (32*3)/342
= 0.28
Oxygen = (16*12)/342
= 0.56
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