The following does NOT indicate that a chemical change
may have taken place is fracture formation. A chemical change happens when the
substance changes its physical state and composition resulting from a chemical
reaction. This chemical reaction may either give off or absorb energy. A change
in color is a chemical change. For example, litmus paper turns to red when
placed in an acid solution. Production of gas is a chemical change. For
example, adding hydrochloric acid to the tiles of the bathroom gives a hissing
sound with gases given off. Formation of a precipitate is also a chemical
change. Change in shape is not a chemical change.
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Answer:
11.9 g of nitrogen monoxide
Explanation:
We'll begin by calculating the number of mole in 6.75 g of NH₃. This can be obtained as follow:
Mass of NH₃ = 6.75 g
Molar mass of NH₃ = 14 + (3×1)
= 14 + 3
= 17 g/mol
Mole of NH₃ =?
Mole = mass /molar mass
Mole of NH₃ = 6.75 / 17
Mole of NH₃ = 0.397 mole
Next, we shall determine the number of mole of NO produced by the reaction of 0.397 mole of NH₃. This can be obtained as follow:
4NH₃ + 5O₂ —> 4NO + 6H₂O
From the balanced equation above,
4 moles of NH₃ reacted to produce 4 moles of NO.
Therefore, 0.397 mole of NH₃ will also react to produce 0.397 mole of NO.
Finally, we shall determine the mass of 0.397 mole of NO. This can be obtained as follow:
Mole of NO = 0.397 mole
Molar mass of NO = 14 + 16 = 30 g/mol
Mass of NO =?
Mass = mole × molar mass
Mass of NO = 0.397 × 30
Mass of NO = 11.9 g
Thus, the mass of NO produced is 11.9 g
In a way, all of the answers could be argued for (for example: in the first option: if the scientists' opinions are understood to be "informed understanding of the causes of events"), but one of the options is the best:
Scientific laws describe specific relationships in nature without offering
an explanation.
The reason why I think this is true is that many laws are phased too short and too concise to provide comprehensive explanations, instead they describe the relationships that must hold.
One of the options is pplain false:
Scientific laws explain why natural events occur. -"Scientific laws were theories that have been tested, proven, and adopted as laws." - since they are not adopted as laws.
I believe the answer would be C, unbalanced.
Since the forces are in opposite directions, and aren't the same size, the answer would be unbalanced.
