The correct answer on edgenuit.y is
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C) Matter changes to a plasma state.</u> </h2>
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Digestive System. it should be the answer its wat sounds right to me
C.) protons , the nucleus contains 2 subatomic particles , one protons & neutrons ( protons have a + charge & neutrons have no electrical charge
Answer:
pH = 9.25
Explanation:
Using H-H equation:
pH = pKa + log [A⁻] / [HA]
<em>Where pH is pH of the buffer</em>
<em>pKa is pKa of the weak acid: 9.24</em>
<em>[A⁻] could be taken as moles of the conjugate base: Moles NH₃</em>
<em>[HA] moles of the weak acid: NH₄⁺</em>
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Initial moles of NH₃:
40.07mL = 0.04007L * (0.3542mol / L) = 0.01419mol
Initial moles NH₄⁺:
0.03501L * (0.3791mol / L) = 0.01327 mol
The HCl added reacts with NH₃ producing NH₄⁺:
HCl + NH₃ → NH₄⁺ + Cl⁻
<em>Moles of HCl:</em>
3.112x10⁻³L * (0.0896mol / L) = 0.00028 moles
That means moles of NH₃ and NH₄⁺ after the addition of HCl are:
<em>NH₄⁺: 0.01327moles + 0.00028moles = 0.01355 moles</em>
<em>NH₃: 0.01419mol - 0.00028 moles = 0.01391 moles</em>
<em />
pH of the buffer is:
pH = pKa + log [A⁻] / [HA]
pH = 9.24 + log [0.01391 moles] / [0.01355 moles]
<h3>pH = 9.25</h3>
Answer:
- <em><u>Option </u></em><u><em>a) element</em></u>
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Explanation:
There are two kind of substances that may be classified as pure substances: elements and compounds.
Elements are the pure substances whose atoms are all of the same kind (same atomic number). Some xamples of pure substances are sodium (Na), oxygen gas (O₂), hydroge gas (H₂), nitrogen gas (N₂), helium (He), and gold (Au). There are 118 known elements. You can find all of them in a periodic table.
Elements cannot be broken down into simpler substances by chemical or physical means because the simplest substance is the atom.
The only way to break elements into other substances is by nuclear reactions: fission and fusion reactions transform the atoms of an element into different atoms, but those reactions are not considered either chemical or physical changes. Nuclear reactions are a completely different kind of changes.
On the other hand, the other kind of pure substances, compounds, are formed by two or more different elements, and they can be broken down into simpler substances by chemical means. For example, water molecules (H₂O) can be broken down into the elements that constitue them, i.e. hydrogen and oxygen.