A electrochemical reaction is said to be spontaneous, if
Answer 1:
Consider reaction: <span>Ni^2+ (aq) + S^2- (aq) ----> + Ni (s) + S (s)
The cell representation of above reaction is given by;
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Hence,

we know that,

and

Therefore,

= - 0.25 - (-0.47) = 0.22 v
Since,
is positive, hence cell reaction is spontaneous
.....................................................................................................................
Answer 2: Consider reaction: <span>Pb^2+ (aq) +H2 (g) ----> Pb (s) +2H^+ (aq)
</span>
The cell representation of above reaction is given by;

Hence,

we know that,

and

Therefore,

= - 0.126 - 0 = -0.126 v
Since,
is negative, hence cell reaction is non-spontaneous.....................................................................................................................
Answer 3:
Consider reaction: <span>2Ag^+ (aq) + Cr(s) ---> 2 Ag (s) +Cr^2+ (aq)
</span>
The cell representation of above reaction is given by;

Hence,

we know that,

and

Therefore,

= - 0.22 - (-0.913) = 0.693 v
Since,
is positive, hence cell reaction is spontaneous
“Models are developed when a scientist’s creativity and insight are combined with data and observations about many similar scenarios”. Models are used for a lot of things in science. As we know everything has advantages and disadvantages, and the same applies to models. Models help us illustrate the concept and formulate hypothesis. When models are used, the scientists are able to notice patterns and develop and revise representation that become a useful model, which makes their scientific knowledge stronger and helps them understand more about the nature of science. Models are a simplified representation. One of the biggest advantages of the model is, that it allows you to have a look at things which are too small such as atoms or too big such as the solar system.
Although, having many benefits, models have quite a number of disadvantages. Models sometimes oversimplify the process therefore leading to a misunderstanding. As models are supposed to be a simplified representation, they will not be complex, which means they will lack detail. For Example “our particle model explains many things about matter, it is not comprehensive — for example, it cannot predict why certain materials have different electrical properties. We could add further refinements that are outside the scope of this course to enable it to do so, but it would make our model so complicated that it would no longer be useful to us”
C, the amount of oxygen produced is the dependent variable since that is what is being measured and it is dependent on which substance is being tested
Answer:
metals donate electrons to nonsmetals