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sasho [114]
2 years ago
6

Which event is an example of an endothermic reaction?.

Chemistry
1 answer:
g100num [7]2 years ago
7 0
For a reaction to be endothermic we have a process where heat is absorbed from a product and the end result is the product being colder than it originally was.

An event that can be a good practical example is using an ice pack on your arm. Your arm is warm before an ice pack is applied. After you apply an ice pack and leave it there for a while and then take it off, the site where the ice pack was would be colder than it was before the ice pack. Hope this helps!
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Consider the data presented below. time (s) 0 40 80 120 160 moles of a 0.100 0.067 0.045 0.030 0.020 part a part complete determ
Whitepunk [10]
To determine which order of the reaction it is, first we need to calculate the rate of change of moles.
the data is as follows 
time         0         40        80       120       160
moles    0.100   0.067  0.045    0.030    0.020


Q1)
for the first 40 s change of moles ;
      = -d[A] / t
      = - (0.067-0.100)/40s
      = 8.25 x 10⁻⁴ mol/s
for the next 40 s
      = -(0.045-0.067)/40
      = 5.5 x 10⁻⁴ mol/s
the 40 s after that
      = -(0.030-0.045)/40 s 
     = 3.75 x 10⁻⁴ mol/s
k - rate constant
and A is the only reactant that affects the rate of the reaction

rate = k [A]ᵇ
8.25 × 10⁻⁴ mol/s = k [0.100 mol]ᵇ ----1
5.5 x 10⁻⁴ mol/s = k [0.067 mol]ᵇ   -----2
divide the 2nd equation by the 1st equation
1.5 = [1.49]ᵇ
b is almost equal to 1
Therefore this is a first order reaction

Q2)
to find out the rate constant(k), we have to first state the equation for a first order reaction.
rate = k[A]ᵇ
As A is the only reactant thats considered for the rate equation. 
Since this is a first order reaction,
b = 1
therefore the reaction is 
rate = k[A]
substituting the values,
8.25 x 10⁻⁴ mol/s = k [0.100 mol]
k = 8.25 x 10⁻⁴ mol/s /0.100mol
   = 8.25 x 10⁻³ s⁻¹

7 0
4 years ago
What happens when an ecosystem reaches the maximum number of individuals it can support
tangare [24]

Answer:

A collapse of the population is rotting, food is not enough and livelihoods have become unfeasible to decrease the number of individuals again.

Another way is to generate mutations to generate a species more vulnerable to decreasing numbers.

In this way the overpopulation is controlled.

Explanation:

In ecosystems, if an increased population breaks the balance of this and begins a new constant adaptation of the extinction of some and overpopulation of others, which may be some chains break or remain unstable.

6 0
3 years ago
a scuba diver's tank contains 0.29g of oxygen compressed into volume of 2.3L. What is the pressure in the tank at 9C?
viva [34]

Answer:

The answer to your question is P = 0.18 atm

Explanation:

Data

mass of O₂ = 0.29 g

Volume = 2.3 l

Pressure = ?

Temperature = 9°C

constant of ideal gases = 0.082 atm l/mol°K

Process

1.- Convert the mass of O₂ to moles

                16 g of O₂ -------------------- 1 mol

                0.29 g of O₂ ----------------   x

                    x = (0.29 x 1)/16

                    x = 0.29/16

                    x = 0.018 moles

2.- Convert the temperature to °K

Temperature = 9 + 273 = 282°K

3.- Use the ideal gas law ro find the answer

              PV = nRT

-Solve for P

              P = nRT/V

-Substitution

              P = (0.018 x 0.082 x 282) / 2.3

-Simplification

              P = 0.416/2.3

-Result

               P = 0.18 atm

5 0
4 years ago
Earth rotates west to east. Is this true or false? I want to say false, but I'm not sure.
777dan777 [17]
The answer is false because it goes in a full 360 degree circle 
8 0
3 years ago
Read 2 more answers
What is the identity of a 100. g sample of metal that, upon absorbing 4680 J of heat, increases in temperature by 52.0°C?
krok68 [10]

The metal is aluminium

<u>Explanation:</u>

Given:

Heat, q = 4680 J

Mass, m = 100g = 0.1kg

ΔT = 52°C

sample = ?

We know:

q = mcΔT

On substituting the value we get:

4680 = 0.1 X c X(52)\\\\c = \frac{4680}{5.2} \\\\c = 900 J/Kg^oC

Thus, the metal is aluminium which has a specific heat capacity of 900 J/kg°C

3 0
4 years ago
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