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3 years ago

What is the half-reaction that occurs at the cathode during the electrolysis of molten potassium bromide?

Physics

1 answer:

polet [3.4K]3 years ago

7 0

The complete ionization of KBr into its constituents is:
KBr (s) ---> K+ (aq) + Br- (aq)

During electrolysis, oxidation takes place at the anode electrode. This means that an ion is stripped off its electron hence becoming more positive:
2 Br- (aq) ---> Br2 (g) + 2e-

We can see that Bromine gas Br2 is evolved at the anode.

Meanwhile at the cathode, the reduction reaction occurs. Which means that the electron from the anode electrode is used to make an ion more negative:
2K+ (aq) + 2e- ---> 2K (s) 
Hence, through reduction, solid potassium is deposited on the plate.

Half reactions:

Anode: 2 Br- (aq) ---> Br2 (g) + 2e-

Cathode: 2K+ (aq) + 2e- ---> 2K (s)

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A tennis player hits a ball 2.0 m above the ground. The ball leaves his racquet with a speed of 20 m/s at an angle 5.0 ∘ above t

goldfiish [28.3K]

Answer:

Explanation:

initial height, yo = 2 m

initial velocity, u = 20 m/s

angle of projection,θ = 5 degree

distance of net = 7 m

height of net = 1 m

Let it covers a vertical distance y in time t .

Use Second equation of motion for vertical motion

$y=y_{0}+uSin\theta t-1/2 gt^{2}$

$y=2+20Sin5 t-4.9t^{2}$

As it hits the ground in time t, so put y = 0

$0=2+1.74 t-4.9t^{2}$

$4.9t^{2}-1.74t-2=0$

$t= \frac{1.74\pm\sqrt{1.74^{2}+4\times\2\times4.9}}{9.8}$

Taking positive sign, t = 0.84 s

The ball travels a horizontal distance x in time t

X = 20 Cos5 x t

X = 16.76 m

As this distance is more than the distance of net, so it clears the net.

Let t' be the time taken to travel a horizontal distance equal to the distance of net

7 = 20 cos5 x t'

t' = 0.35 s

Let the vertical distance traveled by the ball in time t' is y'.

So,

$y'=y_{0}+uSin\theta t'-1/2 gt'^{2}$

$y'=2+20Sin5 t-4.9\times0.35^{2}$

y' = 2.008 m

So, it clears the net which is 1 m high.

It clears the net by a vertical distance of 2.008 - 1 = 1.008 m and horizontal distance 16.76 - 7 = 9.76 m

3 0

3 years ago

A gas occupies a volume of 20 cubic meters at 9,000 pascals. If the pressure is lowered to 5,000 pascals, what volume will the g

forsale [732]

We need to consider no change in the temperature of gas (isothermal transformation)

Volume and pressure are inversely proportional magnitudes, so we can write:

$P_1.V_1=P_2.V_2\\
\\
9.20=5.V_2\\
\\
V_2=\frac{180}{5}=36 \ m^3$

5 0

3 years ago

50200 J of heat are removed from

Dmitry_Shevchenko [17]

Correct Answer:

3.1375

Explanation:

Use equation $Q=mc$ Δ $T$ to find $m$

Plug in all variables $-50200=x\cdot 2000\cdot -8$

Answer: 3.1375

4 0

4 years ago

Light waves are not mechanical waves. The Sun transmits light waves to Earth through __________ _________. *

Natasha2012 [34]

Electromagnetic waves?

3 0

3 years ago

Read 2 more answers

Two objects have a force of gravity of 100 N. If the distance between both objects decreases by a factor of 7, while the masses

Shkiper50 [21]

The gravitational force F between two masses M and m a distance r apart is

F = G M m / r ²

Decrease the distance by a factor of 7 by replacing r with r / 7, and decrease both masses by a factor of 8 by replacing M and m with M / 8 and m / 8, respectively. Then the new force F* is

F* = G (M / 8) (m / 8) / (r / 7)²

F* = (1/64 × G M m) / (1/49 × r ²)

F* = 49/64 × G M m / r ²

In other words, the new force is scaled down by a factor of 49/64 ≈ 0.7656, so the new force has magnitude approx. 76.56 N.

8 0

3 years ago