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DedPeter [7]
3 years ago
12

In a first-order reaction, the half-life is 139 minutes. What is the rate constant?

Chemistry
1 answer:
Valentin [98]3 years ago
3 0

Answer:

a. 8.31 x 10-5 s-1

Explanation:

The general first-order reaction is:

ln[A] = ln[A]₀ -kt

<em>Where [A] is acutal concentration of reactant, initial concentration is [A]₀, k is rate constant and t is time pass</em>

And the equation of the half-life, t 1/2, is:

t_{1/2} = \frac{ln 2}{K}

Has half-life is 139min:

139min * (60s / 1min) = 8340s

t_{1/2} = \frac{ln 2}{8340s}

Half-life is 8.31x10⁻⁵ s⁻¹

<h3>a. 8.31 x 10-5 s-1 </h3>

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larisa86 [58]
Your finger will get burned
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3 years ago
PLEASE HELP
Step2247 [10]

Answer:

See explanation

Explanation:

The equation of the reaction is;

C3H8 + 5O2 ----> 3CO2 + 4H2O

Number of moles of C3H8 = 132.33g/44g/mol = 3 moles

1 mole of C3H8 yields 3 moles of CO2

3 moles of C3H8 yields 3 × 3/1 = 9 moles of CO2

Number of moles of oxygen = 384.00 g/32 g/mol = 12 moles

5 moles of oxygen yields 3 moles of CO2

12 moles of oxygen yields 12 × 3/5 = 7.2 moles of CO2

Hence C3H8 is the limiting reactant.

Mass of CO2 produced = 9 moles of CO2 × 44 g/mol = 396 g of CO2

1 moles of C3H8 yields 4 moles of water

3 moles of C3H8 yields 3 × 4/1 = 12 moles of water

Mass of water = 12 moles of water × 18 g/mol = 216 g of water

b) Actual yield = 269.34 g

Theoretical yield = 396 g

% yield = actual yield/theoretical yield × 100/1

% yield = 269.34 g /396 g × 100

% yield = 68%

4 0
3 years ago
What is a cation and where can you find it on the periodic table?
Maslowich

Answer:

A cation is an ion with fewer electrons than protons. Therefore, it has a positive charge. The electric charge on a proton is equal in amount to the charge on an electron. Anions are atoms or radicals (groups of atoms), that have gained electrons. Since they now have more electrons than protons, anions have a negative charge. Halogens always form anions, alkali metals and alkaline earth metals always form cations. Most other metals form cations (e.g. iron, silver, nickel), whilst most other nonmetals typically form anions (e.g. oxygen, carbon, sulfur).

Explanation:

An anion and cation cannot be specifically found on the periodic table.    

4 0
3 years ago
There are 100.0 grams of each reactant available determine the limiting reactant in this equation
Romashka [77]
Since you have not included the chemical reaction I will explain you in detail.

1) To determine the limiting agent you need two things:

- the balanced chemical equation

- the amount of every reactant involved as per the chemical equation

2) The work is:

- state the mole ratios of all the reactants: these are the ratios of the coefficientes of the reactans in the balanced chemical equation.


- determine the number of moles of each reactant with this formula:

number of moles = (mass in grams) / (molar mass)

- set the proportion with the two ratios (theoretical moles and actual moles)


- compare which reactant is below than the stated by the theoretical ratio.

3) Example: determine the limiting agent in this reaction if there are 100 grams of each reactant:

i) Chemical equation: H₂ + O₂ → H₂O

ii) Balanced chemical equation: 2H₂ + O₂ → 2H₂O

iii) Theoretical mole ration of the reactants: 2 moles H₂ : 1 mol O₂

iv) Covert 100 g of H₂ into number of moles

n = 100g / 2g/mol = 50 mol of H₂

v) Convert 100 g of O₂ to moles: 

n = 100 g / 32 g/mol = 3.125 mol

vi) Actual ratio: 50 mol H₂ / 3.125 mol O₂

vii) Compare the two ratios:

2 mol H₂ / 1 mol O ₂ < 50 mol H₂ / 3.125 mol O₂

Conclusion: the actual ratio of H₂ to O₂ is greater than the theoretical ratio, meaning that the H₂ is in excess respect to the O₂. And that means that O₂ will be consumed completely while some H₂ will remain without react.

Therefore, the O₂ is the limiting reactant in this example.

7 0
3 years ago
Which answer is a scientifically accurate description of velocity?
agasfer [191]

Answer:

B. The motorcyclist traveled southeast along a highway at 55 mph and reached the campsite in less than the two-hour estimated time.

Explanation:

<em>Velocity </em>is the rate at which an object changes position in a specific direction. It has both <em>magnitude and direction.</em>

Travelling <em>southeast</em> at <em>55 mph</em> is a <em>velocity</em>. It gives both speed and direction.

Statements A., B., and C. give the direction but not the speed.

3 0
3 years ago
Read 2 more answers
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