1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
soldi70 [24.7K]
3 years ago
15

Explain how temperature can affect the speed of reaction. Give an example.

Chemistry
1 answer:
aleksley [76]3 years ago
3 0

Answer:

Chemical reactions proceed at different rates. The factors that affect reaction rates are:

surface area of a solid reactant

concentration or pressure of a reactant

temperature

nature of the reactants

presence/absence of a catalyst.

A change in one or more of these factors may alter the rate of a reaction. In this lesson, you will define these factors, and describe and predict their effects on reaction rates.

Surface Area

Surface area is the exposed matter of a solid substance.

Imagine that you are holding a perfect cube of magnesium. The surface area is the sum of the area of all six sides of the cube. The surface area of the cube can be increased by dividing the cube into smaller cubes. Surface area is maximized when a single large cube is crushed to fine powder.

The rate of reaction of a solid substance is related to its surface area. In a reaction between a solid and an aqueous/liquid/gas species, increasing the surface area of the solid-phase reactant increases the number of collisions per second and therefore increases the reaction rate.

In a reaction between magnesium metal and hydrochloric acid, magnesium atoms must collide with the hydrogen ions. When the magnesium atoms form one big lump...

The concentration of a gas is a function of the pressure on the gas. Increasing the pressure of a gas is exactly the same as increasing its concentration. If you have a certain number of gas molecules, you can increase the pressure by forcing them into a smaller volume.

Under higher pressure or at a higher concentration, gas molecules collide more frequently and react at a faster rate. Conversely, increasing the volume of a gas decreases pressure which in turn decreases the collision frequency and thus reduces the reaction rate.

It is important to note however that there are reactions involving gases in which a pressure change does not affect the reaction rate. For this reason, the rates of reactions involving gases have to be determined by experiment.

Also note that solids and liquids are not affected by pressure changes.

Need a good analogy for the effect of concentration on the rate of a chemical reaction?

Temperature

With the exception of some precipitation reactions involving ionic compounds in solution, just about all chemical reactions take place at a faster rate at higher temperatures. The question is why?

Temperature (in Kelvin degrees) is proportional to the kinetic energy of the particles in a substance. For example, if the Kelvin temperature of a substance is doubled, then the average kinetic energy of the particles in that substance is doubled.

 

At higher temperatures, particles collide more frequently and with greater intensity.

 

Here's an analogy.

Imagine that you are baby-sitting a bunch of 6 year olds. You put them in a yard and you let them run around. Every now and then a couple of kids will run into each other. Now imagine that you decide to feed them some sugar. What happens? They run around faster and of course there are many more collisions. Not only that, the collisions are likely to be a lot harder/more intense.

Now, let's look at the effect graphically. Recall that in any sample of matter (the example we used previously was a gas), individual particles have different kinetic energies. Some are moving fast some are moving slowly, and most are moving at some intermediate speed.

Increasing the temperature by say 10°C causes some of the intermediate speed molecules to move faster. The result is more molecules with sufficient kinetic energy to form an activated complex upon collision!

Now consider the relationship between threshold kinetic energy and activation energy. Threshold kinetic energy is the minimum amount of energy required for colliding particles to react - it is the equivalent of activation energy or the minimum potential energy gain required to form an activated complex.

As you can see on the graph, a small increase in temperature can double the number of molecules with the threshold kinetic energy.

Thus there are two effects of increasing temperature: greater collision intensity and more frequent collisions.

A general rule is that a 10°C temperature increase can double a reaction rate. It turns out that the increase in the reaction rate is mainly a function of the more intense collisions. Increased collision frequency is not as significant a factor.

Explanation:

You might be interested in
Give below are the four mixtures. Choose the correct one which can be separated by winnowing. (i) soybean and chickpeas (ii) whe
victus00 [196]

Answer:

Banana wafers and chips

Explanation:

Winnowing is the process of separating heavier and lighter components of a mixture by blowing air through the mixture. This implies that the relative weight of the particles in the mixture determines whether they can be separated by winnowing or not.

However, chips are heavier than wafers. wafers refer to a very light snack which is easily blown away by a current of air. Hence banana chips and wafers can be separated using the method of winnowing.

4 0
3 years ago
Compare the seasons on Titan to the seasons on Earth.
kiruha [24]
Since Titan orbits roughly along Saturn's equatorial plane, and Titan's tilt relative to the sun is about the same as Saturn's, Titan's seasons are on the same schedule as Saturn's—seasons that last more than seven Earth years, and a year that lasts 29 Earth years.
6 0
2 years ago
Consider two gases, A and B, are in a container at room temperature. What effect will the following changes have on the rate of
Oksanka [162]

Answer:

B: increase.

Explanation:

When we are considering two gases A and B in a container at room temperature .

We have to find the change on  rate of reaction when the number of molecules of gases A is doubled

Let [A]=a and [B]=b

A+B\rightarrow product

Rate of reaction

R_1=k[A][B]=kab

We know that concentration is increases with increase in number of moles

When the number of molecules of gases A is doubled then concentration of gases A increases.

Therefore ,[A]=2a

Rate of reaction

R_2=k(2a)(b)=2kab

R_2=2R_1

Hence, the rate of reaction is  2 times the initial rate of reaction.Therefore, the rate of reaction will increase when the number of molecules of gases A is doubled.

Answer: B: increase.

4 0
3 years ago
A 50.0 mL sample of 12.0 M HCl is diluted to 200 mL. What is true about the diluted solution?
kobusy [5.1K]

The concentration of the solution reduces and the number of moles of solute isn't affected.

Data;

  • V1 = 50mL
  • C1 = 12.0M
  • V2 = 200mL
  • C2 = ?
<h3>Facts about the diluted solution</h3>

1. When the solution is diluted, the concentration changes and this time, the concentration reduces.

Using dilution formula

c_1 v_1 = c_2 v_2\\12 * 50 = c_2 * 200\\c_2 = \frac{600}{200} \\c_2 = 3M

The concentration of the solution reduces.

2. The number of moles remains the same.

When a solution is diluted, the number of moles remains the same because there's no change in the mass of the solute.

Learn more on concentration of a solution here;

brainly.com/question/2201903

7 0
2 years ago
Can y’all help me with this science question plz
elixir [45]
The tree I know is producer
7 0
2 years ago
Other questions:
  • For the reaction of oxygen and nitrogen to form nitric oxide, consider the following thermodynamic data (Due to variations in th
    11·1 answer
  • 80.0 ML of fluorine gas is held in a flexible vessel at STP. If the vessel is transported to the surface of Venus where the pres
    5·2 answers
  • If it is raining it is ok for the driver to operate the lift from inside the vehicle.
    9·1 answer
  • Please do question 20 (help)
    9·1 answer
  • What kind of information do unit conversions give?
    11·2 answers
  • Identify a conjugate acid-base pair in the reaction
    13·2 answers
  • If a photon dropping from the n = 7 to the n = 1 level hit the surface of Au, what would be the wavelength of the ejected electr
    8·1 answer
  • Lithium diorganocopper (Gilman) reagents are prepared by treatment of an organolithium compound with copper(I) iodide. Decide wh
    15·1 answer
  • An object is placed at 0 on a number line. It moves 3 units to the right, then 4 units to the left, and then 6 units to the righ
    14·2 answers
  • Which change absorbs heat?
    10·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!