Mole =mass ÷ Mr
∴mass = mole×Mr =0.10 × (23+35.5) = 5.85
the answer is D...
The Mr is obtained from the periodic table
<h3>
Answer:</h3>
CdS
<h3>
Explanation:</h3>
<u>We are given;</u>
- % of cadmium is 78%
- % of sulfur is 22.0%
We are required to determine the empirical formula of cadmium sulfide
<h3>Step 1 : Determine the number of moles of Cadmium and sulfur </h3>
Assuming the mass of the cadmium sulfide is 100 g
Mass of cadmium is 78 g
Mass of sulfur is 22 g
But;
Moles = Mass ÷ Molar mass
Molar mass of Cadmium = 112.411 g/mol
Moles of Cadmium = 78 g ÷ 112.411 g/mol
= 0.694 moles
= 0.69 moles
Molar mass of sulfur is 32.065 g/mol
Moles of sulfur = 22 g ÷ 32.065 g/mol
= 0.686 moles
= 0.69 moles
<h3>Step 3: Determine the whole number mole ratio of Cadmium to sulfur</h3>
Cadmium : Sulfur
Cd : S
0.69 moles : 0.69 moles
0.69/0.69 : 0.69/0.69
1 : 1
Therefore, the empirical formula of greenockite is CdS
Answer:
[A] = 1.438M = 1.4M (Two s.f)
Explanation:
Rate constant, k = 0.00317
Initial Concentration, [A]o = 1.44M
Final Concentration, [A] = ?
Time, t = 0.240 s
Since this is a second order reaction, the formula for this is given as;
1 / [A] = 1 / [A]o + kt
1 / [A] = 1 / 1.44 + (0.00317 * 0.240)
1 / [A] = 0.6944 + 0.0007608
1 / [A] = 0.6952
[A] = 1.438M = 1.4M (Two s.f)
Use this for your answers
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