Sodium Flouride
Magnesium Nitrate
Calcium Phosphate
Sodium Oxide
Lead Iodide
Copper Sulphate
I've answered another one of your questions with the content of how to work these out
Answer:
B.
Explanation:
Minerals are formed due to chemical composition by rocks are pressured into their formed from dirt and naturally hard things.
The half-life of Th-232 is 1.405 × 10¹⁰ years
Time elapsed = 2.8 x 10⁹ years
Equation of radioactive decay:
A = A₀ = (1/2)^ t/t₁/₂
where A₀ is the initial amount, A is the amount after time t, t₁/₂ is the half file
The fraction of thorium-232 that remains in the rock after 2.8 billions years is,
A/A₀ = (1/2) ^ (2.8 x 10⁹/ 1.405 × 10¹⁰) = 0.871
Therefore, the percentage of thorium-232 in the rock that was dated at 2.8 billions year = 87.1%
Answer:
Kc → 5.58×10⁻⁴
Explanation:
Equilibrium reaction is:
2NOCl (g) ⇄ 2NO (g) + Cl₂(g)
Initially we have 1.25 moles of NOCl
After the equilibrium, we have 1.10 moles. So, during the process:
(1.25 mol - 1.1 mol) = 0.15 moles have reacted.
As ratio are 2:2, and 2:1, 0.15 moles of NO and (0.15 /2) = 0.075 moles of chlorine, were produced in the equilibrium.
Finally in equilibrium we have: 1.10 moles of NOCl, 0.15 moles of NO and 0.075 moles of Cl₂. But these amount are not molar, so we need molar concentration in order to determine Kc:
1.10 mol /2.50L = 0.44 M
0.15 mol / /2.50L = 0.06 M
0.075 mol /2.50L = 0.03 M
Let's make expression for Kc → [Cl₂] . [NO]² / [NOCl]²
Kc = (0.03 . 0.06²) / 0.44² → 5.58×10⁻⁴
