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4 years ago

If the activation energy required for a chemical reaction were reduced

Physics

1 answer:

Dmitry [639]4 years ago

3 0

Answer:

The rate of the reaction would increase.

Explanation:

The activation energy in chemistry and biology is the energy that a system needs before it can start a certain process. The activation energy is usually used to designate the minimum energy necessary for a given chemical reaction to occur. For a reaction to occur between two molecules, they must collide in the correct orientation and have a minimum amount of energy. As the molecules approach, their electron clouds repel. This requires energy (activation energy) and comes from the heat of the system, that is, the translational, vibrational energy of each molecule.

The activation energy of the reaction corresponds to the energy necessary for the reaction to be carried out with less reagent energy. The lower the activation energy of a reaction, the higher the speed of the reaction.

A reaction is called exothermic when it provides for the medium a higher energy than is necessary to reach the activated complex.

When a reaction is endothermic, it provides for the environment a lower energy than is necessary to reach the activated complex.

Catalysts are substances that decrease the activation energy for a given reaction, without altering its ΔH. The catalysts do not alter during the reactions.

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Assume that the upward direction is positive and the downward direction is negative. What is the ball's velocity (in m/s) when i

LenaWriter [7]

The given question is incomplete. The complete question is as follows.

You throw a ball vertically upward, and as it leaves your hand, its speed is 26.0 m/s.

(a) How high (in m) does it rise above the level where it leaves your hand?

(b) How long (in s) does it take to reach its highest point?

(c) How long (in s) does the ball take to return to the level where it left your hand after it reaches its highest point?

(d) Assume that the upward direction is positive and the downward direction is negative. What is the ball's velocity (in m/s) when it returns to the level where it left your hand? (Indicate the direction with the sign of your answer.)

Explanation:

(a) For maximum height, the formula will be as follows.

$v^{2} = u^{2} + 2as$

a = $v^{2} - 2gh$

or, h = $\frac{v^{2}}{2g}$

= $\frac{(26)^{2}}{2 \times 9.8}$

= $\frac{676}{19.6}$

= 34.5 m/s

Hence, it rises 34.5 m/s above the level where it leaves your hand.

(b) Time to reach maximum height is as follows.

v = u + at

or, v - gt = 0

t = $\frac{v}{g}$

= $\frac{26}{10}$

= 2.6 sec

Therefore, it will take 2.6 sec to reach its highest point.

(c) Time taken by the ball to ascent is equal to the time it has taken to descent.

Therefore, time taken by the ball to return to the level where it left your hand after it reaches its highest point? is also 2.6 sec.

(d) Speed of the ball will be 26 m/s in the downward direction. Hence, the velocity will be -26 m/s.

3 0

3 years ago

A student uses a spring loaded launcher to launch a marble vertically in the air. The mass of the marble is

GarryVolchara [31]

Answer:

Part a)

When spring compressed by 2 cm

H = 1.47 m

Part b)

When spring is compressed by 4 cm

H = 5.94 m

Explanation:

Part a)

As we know that the spring is compressed and released

so here spring potential energy is converted into gravitational potential energy at its maximum height

So we will have

$\frac{1}{2}kx^2 = mg(H + x)$

$0.5(220)(0.02)^2 = 0.003(9.81)(H + 0.02)$

so we have

$H = 1.47 m$

Part b)

Similarly when spring is compressed by 4 cm

then we have

$\frac{1}{2}kx^2 = mg(H + x)$

$0.5(220)(0.04)^2 = 0.003(9.81)(H + 0.04)$

so we have

$H = 5.94 m$

8 0

4 years ago

Two workers are sliding 300 kg crate across the floor. One worker pushes forward on the crate with a force of 400 N while the ot

almond37 [142]

Answer:

The kinetic coefficient of friction of the crate is 0.235.

Explanation:

As a first step, we need to construct a free body diagram for the crate, which is included below as attachment. Let supposed that forces exerted on the crate by both workers are in the positive direction. According to the Newton's First Law, a body is unable to change its state of motion when it is at rest or moves uniformly (at constant velocity). In consequence, magnitud of friction force must be equal to the sum of the two external forces. The equations of equilibrium of the crate are:

$\Sigma F_{x} = P+T-\mu_{k}\cdot N = 0$ (Ec. 1)