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The complete question probably is
The pH scale for acidity is defined by pH = − log₁₀[H⁺] where [H⁺] is the concentration of hydrogen ions measured in moles per liter (M). A solution has a pH of 2.55. Find the hydrogen ion concentration.
Answer: -
0.003 M
Explanation: -
pH = − log₁₀[H⁺]
Thus the hydrogen ion concentration [H⁺] = 
= 
= 0.003 M
Answer:
Explanation:
One of the properties of a liquid is that, <u>it's particles move freely (not tightly packed)</u> hence the reason for <u>it's free flowing (no definite shape)</u> when shaken in a container, unlike a solid whose <u>particles are tightly packed with restricted/no movement</u> and hence the reason for it's compactness and it's definite shape.
When a plastic solid (whose particle is tightly packed and have a restricted movement/no movement) is placed near a heat source, <u>it's particles gains energy in the process and starts to move (though slightly free) and become less tightly packed</u> hence the reason it is observed that plastic solids near a heat source melts.
From the above, it can be deduced that a liquid and a plastic solid near a heat source <u>have there particles move freely (and not tightly packed) hence making the two substances flow freely with no definite shape.</u>
Mass % of nitrogen = mass of nitrogen*100 / total mass
= 14*100 / (1+ 14 + 32)
= 14*100 / 47
= 29.7 %
Answer:
pH = 5.47
Explanation:
The equilibrium that takes place is:
HIO ↔ H⁺ + IO⁻
Ka =
= 2.3 * 10⁻¹¹
At equilibrium:
<u>Replacing those values in the equation for Ka and solving for x:</u>

Then [H⁺]=3.39 * 10⁻⁶, thus pH = 5.47
Answer:
The mass of oxygen is 12.10 g.
Explanation:
The decomposition reaction of potassium chlorate is the following:
2KClO₃(s) → 2KCl(s) + 3O₂(g)
We need to find the number of moles of KClO₃:

Where:
m: is the mass = 30.86 g
M: is the molar mass = 122.55 g/mol
Now, we can find the number of moles of O₂ knowing that the ratio between KClO₃ and O₂ is 2:3
Finally, the mass of O₂ is:

Therefore, the mass of oxygen is 12.10 g.
I hope it helps you!