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;
</span>

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
A) The class and C) Family would be the only accurate option. Here are the levels from largest to smallest: <span>kingdom, phylum, class, order, family, genus and species.</span>
Answer:
The second student with mass 70kg has more momentum
Explanation:
Using the formula:
p = m × v
Where;
p = momentum (kgm/s)
m = mass (kg)
v = velocity (m/s)
According to this question, two students are running in a cross country race.
Student 1 has the following; m = 60kg, v = 7m/s
Student 2 has the following; m = 70kg, v = 7m/s
Using p = mv
Student 1, p = 60 × 7 = 420 kgm/s
Student 2, p = 70 × 7 = 490 kgm/s
From the result of the above calculations, student 2 with mass 70kg has more momentum.