Answer:
Two Half-lives
Explanation:
Let number of Parent nuclei Initially present be X,
Then, finally 
Parent nuclei Will remain with 
daughter nuclei.
In one half- life , parent nuclei becomes half of initial.
So, starting with X parent nuclei,
After one half-life, it will degrade to 
.
After another half life , Parent nuclei will become half of
Which is equal to .
So, Parent nuclei have to go through Two half-lives.
The balanced chemical reaction:
C3H8 + 5O2 = 3CO2 + 4H2O
We are given the amount of the carbon dioxide to be produced. This will be the starting point of our calculations.
<span>43.62 L CO2 ( 1 mol CO2 / 22.4 L CO2 ) (5 mol O2 / 3 mol CO2 ) (
22.4 L O2 / 1 mol O2) = 72.7 L O2</span>
When reactants are mixed and heated and liquid collects in the sidearm of the apparatus, a chemical reaction is occurring.
<h3>What is a chemical reaction?</h3>
A chemical reaction is said to occur when reactants are combined to form products. We must note that the formation of products is evidenced by;
- Appearance of a liquid
- Appearance of a gas
- Appearance of a solid
Hence, when reactants are mixed and heated and liquid collects in the sidearm of the apparatus, a chemical reaction is occurring.
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Answer:
Mass = 2.355 g
Explanation:
Given data:
Mass of K₂O needed = ?
Mass of KNO₃ produced = 5.00 g
Solution:
Chemical equation:
K₂O + Ca(NO₃)₂ → CaO + 2KNO₃
Number of moles of KNO₃:
Number of moles = mass/molar mass
Number of moles = 5.00 g/ 101.1 g/mol
Number of moles = 0.05 mol
now we will compare the moles of KNO₃ and K₂O.
KNO₃ : K₂O
2 : 1
0.05 : 1/2×0.05 = 0.025 mol
Mass of potassium oxide needed in gram:
Mass = number of moles × molar mass
Mass = 0.025 mol × 94.2 g/mol
Mass = 2.355 g
The amount of Al that would be needed will be 0.79 grams
<h3>Stoichiometric calculations</h3>
From the equation of the reaction below:
The mole ratio of Al to 
is 2:3.
Mole of 71.8 mL. 0.610 M = 0.610 x 71.8/1000 = 0.0438 moles
Equivalent mole of Al = 2/3 x 0.0438 = 0.029 moles
Mass of o.o29 moles Al = 0.029 x 26.98 = 0.79 grams
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