Three signs that a chemical change has taken place is 1) color change 2) formation of gas bubbles 3) a change in temperature ( if you have ever bleached your hair the reason why it is warm to the touch is because of a chemical reaction)
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Answer:
2 C6H14 (g) + 19 O2 (g) --> 12 CO2 (g) + 14 H2O (g)
Explanation:
For solving the stoichiometric calculations, we first need to do two steps. One of them is balancing the reaction equation. Here the balancing is done and we can see that 2 moles of hexane reacts with 19 moles of oxygen to produce 12 moles of carbon dioxide and 14 moles of water.
Now, for 2 moles of hexane, number of moles of oxygen required is 19.
So, for 7.2 moles of hexane, number of moles of oxygen required is.
= 68.4.
So 68.4 moles of oxygen is required.
Answer:
The solar energy is converted to chemical energy by the process of photosynthesis - This is the true statement of the given question.
Explanation:
An ecosystem usually refers to the biological community comprising all the types of living species that are continuously interacting with the surrounding environment. Most of these ecosystems are solar-powered, and by this phrase, it means that there occurs the transformation of energy from solar to chemical energy which is taking place due to the process of photosynthesis. Both the terrestrial and the aquatic, are able to carry out this process in the presence of sunlight, water, and CO₂, and in return, it liberates food and oxygen into the ecosystem.
Thus, this statement satisfies the given phrase.
All other options are false as it does not justify the phrase.
<u>Answer:</u> The above reaction is non-spontaneous.
<u>Explanation:</u>
For the given chemical reaction:
Here, nickel is getting reduced because it is gaining electrons and iron is getting oxidized because it is loosing electrons.
We know that:
Substance getting oxidized always act as anode and the one getting reduced always act as cathode.
To calculate the 
of the reaction, we use the equation:
Relationship between standard Gibbs free energy and standard electrode potential follows:
As, the standard electrode potential of the cell is coming out to be negative for the above cell. Thus, the standard Gibbs free energy change of the reaction will become positive making the reaction non-spontaneous.
Hence, the above reaction is non-spontaneous.
