The half life of a substance is the time taken by a radioactive substance to decay by half its original mass. In this case, the half life of Potassium-40 is 1.3 billion years.
Original mass of Potassium-40 = 12 g (100%)
New mass after the decay = 3 g ( 25 %, since 75% was replaced by argon)
New mass = Original mass × (1/2)^n ; where n is the number of half lives.
3 = 12 × (1/2)^n
(1/2)^n = 1/4
n = 2
Therefore; the time taken will be 1.3 × 2 = 2.6 Billion years
Answer:
Fatty acid
Explanation:
A fatty acid is a carboxylic acid with a long chain of 12 or more carbons.
If the molecule has no other distinguishing features, the compound is hexacosanoic acid, CH₃(CH₂)₂₄COOH.
Answer:
C = 75%
Explanation:
Theoretical yield = 8.17g
Actual yield = 6.13g
To calculate the percentage yield of a compound in a reaction, we'll use the formula to calculate it
Percentage yield = (actual yield / theoretical yield) * 100
% yield = (6.13/8.17) * 100
Percentage yield = 0.7503 * 100
Percentage yield = 75.03%
To find density, use <span>p=m/V, which means density equals mass divided by volume.
If the volume is 15.625 cm^3 and the mass is 10 grams, just divide 10 by 15.625.
10/15.625 = 0.64
So the density is 0.64</span><span> mass per unit volume.</span>
1.3 x 10²⁴molecules
Explanation:
Given parameters:
Mass of Mn(SO₄)₂ = 542.32g
Unknown:
Number of molecules in the compound = ?
Solution:
The number of moles is the unit used to express the number of particles in a substance.
A mole contains 6.02 x 10²³ molecules
Number of moles = 
Molar mass Mn(SO₄)₂ = 55 + 2(32 + 4(16)) = 247g/mol
Number of moles = 
= 2.2moles
1 mole = 6.02 x 10²³ molecules
2.2 moles = 2.2 x 6.02 x 10²³ molecules = 1.3 x 10²⁴molecules
learn more:
Number of moles brainly.com/question/1841136
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