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WITCHER [35]
2 years ago
12

If the amount of radioactive sodium-24, used for studies of electrolytes within the body, in a sample decreases from 0.8 to 0.2

mg in 30.0 h , what is the half-life of sodium-24?
Chemistry
1 answer:
kirill [66]2 years ago
6 0

Answer:

15 h

Explanation:

Okay, the first thing that we all have to know before we can answer this question is that this Topic that is, Chemistry of Radioactivity is related to kinetics in a way that Radioactive disintegration follows the first order of Reaction which is under kinetics. So, we will be using the first order kinetics rate law to answer this question. Using the equation (1) below;

k =[ 2.303/ t ]×log ([N°}/ [Nr]) --------(1).

We are given from the question that N° = initial sample = 0.8 mg and Nr= sample remaining = 0.2 and the time taken = t= 30.0 h.

k= (2.303/ 30.0 h ) × log (0.8/0.2).

k=0.076768 h^-1 × log (4).

k= 0.076768 h^-1 × 0.6021.

k= 0.0462 h^-1.

Therefore, using the formula for Calculating half life below for first order kinetics we will be able to find out answer.

k = ln 2/ t(1/2). Where t(1/2) is the half life.

t(1/2) = ln 2/ k.

t(1/2) = ln 2 / 0.0462 h^-1.

t(1/2)= 0.6931/0.0462 h^-1.

t(1/2)=15 h

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4 0
3 years ago
At 338 mm hg and 72 c a sample of carbon monoxide gas occupies a volune of 0.225 L the gas transferred to a 1.50 L flask and the
Elis [28]

Answer:

P₂  = 0.09 atm

Explanation:

According to general gas equation:

P₁V₁/T₁ = P₂V₂/T₂

Given data:

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Initial pressure = 338 mmHg (338/760 =0.445 atm)

Initial temperature = 72 °C (72 +273 = 345 K)

Final temperature = -15°C (-15+273 = 258 K)

Final volume = 1.50 L

Final pressure = ?

Solution:

P₁V₁/T₁ = P₂V₂/T₂

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P₂ = 0.445 atm × 0.225 L × 258 K / 345 K × 1.50 L

P₂  =  25.83 atm .L.  K  / 293 K . L

P₂  = 0.09 atm

7 0
3 years ago
Consider the following voltaic cell:(j) In which direction do anions within the salt bridge move to maintain charge neutrality?
aniked [119]

In order to maintain neutrality, the negatively charged ions in the salt bridge will migrate into the anodic half-cell. A similar (but reversed) situation is found in the cathodic cell.

<h3>What purpose does a salt bridge serve in an oxidation process?</h3>

Anions (negatively charged particles) are added to the solution of the oxidation half of the cell by the salt bridge, and cations (positively charged particles) are added to the solution of the reduction half of the reaction. 

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For instance, KCl, AgNO3, etc. In a galvanic cell, such as a voltaic cell or Daniel cell, salt bridges are typically used. A salt bridge's primary job is to assist in preserving the electrical neutrality of the internal circuit. Additionally, it aids in keeping the cell's response from reaching equilibrium.

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7 0
1 year ago
Eric's father asked an engineer to survey the field behind their house. He wanted to plant some apple and pear trees there. Acco
Vsevolod [243]

Answer:

11,000 cm

Explanation:

Step 1: Given data

Width of the field (w): 17 meters

Length of the field (l): 38 meters

Step 2: Calculate the perimeter of the field

The field is a rectangle. We can find its perimeter (P) by adding its sides.

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Step 3: Convert the perimeter to centimeters

We will use the relationship 1 m = 100 cm.

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8 0
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2. Ice will melt at a temperature above 32 degrees fahrenheit 0 degrees celsius.

3. water boils at 212 degrees fahrenheit or 100 degrees celsius.

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