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Gnesinka [82]
1 year ago
11

nuclear decay occurs according to first-order kinetics. a nuclide decays in 3.40 days from 45.0 g to 12.1 g. what is the rate co

nstant for the nuclide?
Chemistry
1 answer:
Ad libitum [116K]1 year ago
4 0

The rate constant for the nuclide according to first-order kinetics is 0.3863 per day.

Nuclear Decay in First-Order Kinetics:

m(t) = Me∧(-αt)

where m(t) = mass of nuclide after decay at time t;

M = mass of nuclide before decay;

α = rate constant of decay;

t = time for the decay;

<h3>What is first-order kinetics?</h3>

When a fixed percentage of the drug is excreted per unit of time, this is known as first-order kinetics.

For example, The amount of drug in the body has a direct relationship to the rate of removal. The amount of medication eliminated per unit of time increases with concentration. The medication concentration decreases by 50% for each half-life.

Now,

m(t) = Me∧(-αt)

⇒e∧(αt) = M/m(t)

applying ln on both sides;

αt = ln(m/m(t))

α = (ln(m/m(t))/t)

here t= 3.4 days, M = 45 grams, m(t) = 12.1 grams;

dropping these values in the above equation we get,

α = 0.3863 per day;

The rate constant for the nuclide according to first-order kinetics is 0.3863 per day.

To refer more about First Order Kinetics visit:

brainly.com/question/14977977

#SPJ4

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For a cell whose potential is –0.46 v with 3 moles of electrons exchanged, what is ΔG ? ΔG = –nFE°cell
Nimfa-mama [501]
<span>ΔG is 133kJ
</span>
ΔG = –nFE°cell
ΔG =  free energy of the reaction = ?
n = no of moles of electrons exchanged in the reaction = 3
F = Faraday's constant (9.648456 x 10^{4}C/mol)E_{0} =  cell potential = <span>–0.46 v
</span>
⇒ ΔG = –nFE°cell
⇒ ΔG = - (3 mol)(9.648456 x 10^{4} C/mol) (-0.46 J/C) ⇒ ΔG = +133148 J ≈ 133 kJ
4 0
4 years ago
Read 2 more answers
Plz AWNSER all these questions quickly i gonna make Christmas presents
topjm [15]

Answer:

Photosynthesis is Endothermic reaction.

Explanation:

Photosynthesis:

It is the process in which in the presence of sun light and chlorophyll by using carbon dioxide and water plants produce the oxygen and glucose.

Word equation:

Carbon dioxide + water + energy →   glucose + oxygen

Chemical equation:

6H₂O + 6CO₂ + energy  →   C₆H₁₂O₆ + 6O₂

it is known from balanced chemical equation that 6 moles of carbon dioxide react with the six moles of water and created one mole of glucose and six mole of oxygen.

water is supplied through the roots, carbon dioxide collected through stomata and sun light is capture  by chloroplast.

The energy required for this reaction is taken from sun.

While other given reactions are exothermic reactions.

2)

Answer:

Exothermic

Explanation:

Exothermic reaction:

The type of reactions in which energy is released are called exothermic reactions.

In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.

For example:

When acid and base are react heat is produced. The flask in which reaction is proceed is warm when we touch it. It indicate the exothermic reaction.

Chemical equation:

NaOH + HCl → NaCl + H₂O + heat

3)

Answer:

Heat is released

Explanation:

Exothermic reaction:

The type of reactions in which energy is released are called exothermic reactions.

In this type of reaction energy needed to break the bonds are less than the energy released during the bond formation.

For example:

Chemical equation:

C + O₂   →  CO₂

ΔH = -393 Kj/mol

it can be written as,

C + O₂   →  CO₂ + 393 Kj/mol

7 0
4 years ago
Balance the double replacement: <br> Mn(SO4)2 + K2S2O3 =
Firlakuza [10]

Answer:

        Mn(SO₄)₂ + 2 K₂S₂O₃ ----------> Mn(S₂O₃)₂ + 2 K₂SO₄

Explanation:

Reaction Given:

              Mn(SO₄)₂ + K₂S₂O₃ =

Balance Equation = ?

Solution:

Balance Chemical Equation:

A balanced chemical equation is that in which the number of the reactant atoms equal to the number of the product atom.

For example if the Sulfur at the reactant side is 6, the number of Sulfurmust be 6 on the product side.

First we Complete the reaction

                  Mn(SO₄)₂ + K₂S₂O₃ ----------> Mn(S₂O₃)₂ + K₂SO₄

Check the chemical equation and count the number of atoms at the reactant side and product side.

If the number of atoms of the reactants equal to the number of atoms of products then the reaction is balanced but if not equal, then reaction is not balanced

Balancing is an trial and error process to get a balance reaction.

First we count the number of atoms of reactant and product

             Mn(SO₄)₂ + K₂S₂O₃ ----------> Mn(S₂O₃)₂ + K₂SO₄

Number of atoms of Reactant:

Mn = 1

S = 4

O = 7

K = 2

Number of atoms of Product:

Mn = 1

S = 5

O = 10

K = 2

So this is not a balance equation as the atoms of the reactant atoms not equal to the number of the product atoms.

As there are 4 Sulfur, and 7 oxygen atoms at reactant side but 5 Sulfur, and 10 oxygen atoms at the product side so we balance this along with other

Balanced Equation:

          Mn(SO₄)₂ + 2 K₂S₂O₃ ----------> Mn(S₂O₃)₂ + 2 K₂SO₄

Now count the number of atoms of reactant and product

Number of atoms of Reactant:

Mn = 1

S = 6

O = 14

K = 4

Number of atoms of Product:

Mn = 1

S = 5

O = 10

K = 2

Now this reaction is balanced as the atoms of the reactant atoms equal to the number of the product atoms.

So,

the Coefficient of  K₂S₂O₃ and K₂SO₄ is 2 in balanced equation

4 0
3 years ago
A bird could be both a consumer and a producer
Ilia_Sergeevich [38]
False, only Consumers.
4 0
4 years ago
Calculate the molality for each of the following solutions. Then, calculate the freezing-point depression ΔTF = iKFcm produced b
zlopas [31]

Answer:

a) Cm= 3.9 m  ; ΔTf= 14.51 ºC

b) Cm= 0.21 m ; ΔTf= 0.79ºC

Explanation:

In order to solve the problems, we have to remember that the molality (m) of a solution is equal to moles of solute in 1 kg of solvent.

m= mol solute/kg solvent

a) In this case we have molarity, which is moles of solute in 1 liter of solution. We have to know how many kg of solvent (water) we have in 1 L of solution.

3.2 M NaCl= 3.2 mol NaCl/ 1 L solution

1 L solution= 1000 ml solution x 1.00 g/ml= 1000 g

A solution is composed by solute (NaCl) + solvent, so:

1000 g solution = g NaCl + g solvent

g NaCl= 3.2 mol NaCl x 58.44 g/mol= 187 g NaCl

g solvent= 1000 g - 187 g NaCl= 813 g= 0.813 kg

Cm= 3.2 g NaCl/0.813 kg solvent= 3.9 m

NaCl is an electrolyte and it dissociates in water in two ions: Na⁺ anc Cl⁻, si the van't Hoff factor (i) is 2.

ΔTf= i x KF x Cm= 2 x 1.86ºC/m x 3.9 m= 14.51ºC

b) In this case we have 24 g of solute in 1.5 L of solvent. We have to convert the liters of solvent to kg, and to convert the mass of solute to mol by using the molecular weight of KCl (74.55 g/mol):

24 g KCl x 1 mol KCl/74.55 g= 0.32 mol

1.5 L solvent= 1500 g solvent x 1.00 g/ml= 1500 g = 1.5 kg

Cm= 0.32 g KCl/1.5 kg solvent= 0.21 m

KCl is an electrolyte and when it dissolves in water, it dissociates in 2 ions: K⁺ and Cl⁻. For this, van't Hoff factor (i) is equal to 2.

ΔTf= i x KF x Cm= 2 x 1.86ºC x 0.21 m= 0.79ºC

7 0
4 years ago
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