1. The half-life of the element is 22 years
2. The time taken for 308 g of the sample to decay to 4.8125 g is 132 years
<h3>Definition of half-life </h3>
Half-life is simply defined as the time taken for half of a material to decay.
<h3>1. How to determine the half-life </h3>
- Original amount (N₀) = 45 g
- Half of the original amount = 45 / 2 = 22.5 g
From the diagram, the time for 22.5 g is 22 years.
Thus, the half-life of the element is 22 years
<h3>2. How to determine the time </h3><h3>i. Determination of the number of half-lives </h3>
- Original amount (N₀) = 308 g
- Amount remaining (N) = 4.8125 g
- Number of half-lives (n) =?
2ⁿ = N₀ / N
2ⁿ = 308 / 4.8125
2ⁿ = 64
2ⁿ = 2⁶
n = 6
<h3>ii. Determination of the time </h3>
- Number of half-lives (n) = 6
- Half-life (t½) = 22 years
t = n × t½
t = 6 × 22
t = 132 years
See attached photo for diagram
Learn more about half life:
brainly.com/question/26374513
Answer:
When an atom is in an excited state, the electron can drop all the way to the ground state in one go, or stop on the way in an intermediate level. Electrons do not stay in excited states for very long - they soon return to their ground states, emitting a photon with the same energy as the one that was absorbed.
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Explanation:
Answer:
grams of oxygen = 21.40 g
Explanation:
octane → C8H18
The chemical reaction needs to be represented with a chemical equation before solving. The equation also need to be balanced.
C8H18 + O2 → CO2 + H2O
Balanced equation
2C8H18 + 25O2 → 16CO2 + 18H2O
Molar mass of octane = 12 × 8 + 18 = 96 + 18 = 114 g
Mass of octane in the chemical equation = 2 (114) = 228 g
molar mass of oxygen = 32 g
mass of oxygen in the chemical equation = 25 × 32 = 800 g
if 228 g of octane react with 800 g of oxygen
6.1 g of octane will require ? grams of oxygen
cross multiply
grams of oxygen = 6.1 × 800/228
grams of oxygen = 4880
/228
grams of oxygen = 21.4035087719
grams of oxygen = 21.40 g
