Answer:
2 KMnO4 → K2MnO4 + MnO2(s) + O
Explanation:
Here, the oxidation state of manganese changes as the potassium permanganate (oxidation state +7) decomposes to potassium manganate (oxidation state +6) and manganese dioxide (oxidation state +4). Oxygen gas is also liberated.
Answer:
4.22 × 10 ⁻²² mol
Explanation:
Given data:
Number of molecules of bromine = 254 molecules
Number of moles = ?
Solution:
1 mole = 6.02 × 10 ²³ molecules
254 molecules × 1 mol / 6.02 × 10 ²³ molecules
42.2 × 10 ⁻²³ mol
4.22 × 10 ⁻²² mol
<h2>Solutions:</h2>
<u>Case a:</u> Finding pH for [H⁺] = 1.75 × 10⁻⁵ mol/L :
As we know pH is given as,
pH = -log [H⁺]
Putting value,
pH = -log [1.75 x 10⁻⁵]
pH = 4.75
<u>Case b:</u> Finding pH for [H⁺] = 6.50 × 10⁻¹⁰ mol/L :
As we know pH is given as,
pH = -log [H⁺]
Putting value,
pH = -log [6.50 × 10⁻¹⁰]
pH = 9.18
<u>Case c:</u> Finding pH for [H⁺] = 1.0 × 10⁻⁴ mol/L :
As we know pH is given as,
pH = -log [H⁺]
Putting value,
pH = -log [1.0 × 10⁻⁴]
pH = 4
<u>Case d:</u> Finding pH for [H⁺] = 1.50 × 10⁻⁵ mol/L :
As we know pH is given as,
pH = -log [H⁺]
Putting value,
pH = -log [1.50 × 10⁻⁵]
pH = 4.82
Answer:- 0.88
Solution:- Masses of silver and copper metals are given and we are asked to calculate the percentage of silver in the alloy.
mass percent of Ag = 
Mass of Ag = 17.6 g
mass of Cu = 2.40 g
mass of alloy = 17.6 g + 2.40 g = 20.0 g
Let's plug in the values in the formula:
mass percentage of Ag = 
mass percentage of Ag = 88%
So, the mass percentage of silver in sterling silver is 88% and in decimal form it is 0.88.
