Answer:
b)5l x 10kg c)10kg + 9l (Not sure for the last 1)
Sodium-22 remain : 1.13 g
<h3>Further explanation
</h3>
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually, radioactive elements have an unstable atomic nucleus.
General formulas used in decay:

T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
half-life = t 1/2=2.6 years
T=15.6 years
No=72.5 g

Answer:
Calendar and periodic table both have repetitive patterns.
Explanation:
In calendar the days are arranged and divided into weeks whereas in the periodic table the elements are arranged in increasing atomic number and divided into groups
The scientific geographic name is usually a great election
Answer:
235 g
Explanation:
From the question;
- Volume is 400.0 mL
- Molarity of a solution is 4.25 M
We need to determine the mass of the solute K₂CO₃,
we know that;
Molarity = Number of moles ÷ Volume
Therefore;
First we determine the number of moles of the solute;
Moles = Molarity × volume
Moles of K₂CO₃ = 4.25 M × 0.4 L
= 1.7 moles
Secondly, we determine the mass of K₂CO₃,
We know that;
Mass = Moles × Molar mass
Molar mass of K₂CO₃, is 138.205 g/mol
Therefore;
Mass = 1.7 moles × 138.205 g/mol
= 234.9485 g
= 235 g
Thus, the mass of K₂CO₃ needed is 235 g