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mestny [16]
3 years ago
7

A nonmetal

Chemistry
1 answer:
mars1129 [50]3 years ago
5 0

^{16}_{\phantom{1}8}\text{O}.

Oxygen-16 is the atom in question.

  • Atomic number: 8.
  • Mass number: 16.
<h3>Explanation</h3>

The superscript of the ion says "2-". That means that the ion here carries a charge of -2.

  • The charge is negative, meaning that there are more electrons (which are negative) than protons (which are positive) in that ion.
  • The size of the charge is 2. There are two more electrons than protons in that ion.

There are 10 electrons in total in that ion. There are two more electrons than protons. That means that there are 10 - 2 = 8 protons in that ion.

The atomic number of an atom is the same as its number of protons. The atomic number of X is 8.

The atomic number determines the element. Atomic number 8 is oxygen. Thus element X is oxygen.

Mass number is the sum of number of protons and neutrons in an atom. 8 + 8 = 16 for this atom.

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Determine the volume in liters occupied by 22.6 g of I2 gas at STP.
AleksandrR [38]

 The volume in liters  occupied  by 22.6 g  of I₂  gas  at STP  is  1.99 L (answer A)

 <u><em>calculation</em></u>

Step: find the  moles of I₂

moles= mass÷  molar mass

from  periodic table the  molar mass  of I₂  is  253.8 g/mol

moles = 22.6 g÷253.8 g/mol =0.089 moles

Step 2:find the volume  of I₂  at STP

At STP  1  moles =22.4 L

         0.089 moles= ? L

<em>by cross  multiplication</em>

={ (0.089 moles x 22.4 L) /1 mole} = 1.99 L


6 0
3 years ago
A solution is diluted by adding more _____, which means the _____ of the solution increases but the amount (moles) of solute sta
Rudik [331]

Answer:solvent ; volume

Explanation:

6 0
2 years ago
Which of these half-reactions represents reduction?
gogolik [260]

Answer: The half-reactions represents reduction are as follows.

  • Cr_{2}O^{2-}_{7} \rightarrow Cr^{3+}
  • MnO^{-}_{4} \rightarrow Mn^{2+}

Explanation:

A half-reaction where addition of electrons take place or a reaction where decrease in oxidation state of an element  takes place is called reduction-half reaction.

For example, the oxidation state of Cr in Cr_{2}O^{2-}_{7} is +6 which is getting converted into +3, that is, decrease in oxidation state is taking place as follows.

Cr_{2}O^{2-}_{7} + 3 e^{-} \rightarrow Cr^{3+}

Similarly, oxidation state of Mn in MnO^{-}_{4} is +7 which is getting converted into +2, that is, decrease in oxidation state is taking place as follows.

MnO^{2-}_{4} + 5 e^{-} \rightarrow Mn^{2+}

Thus, we can conclude that half-reactions represents reduction are as follows.

  • Cr_{2}O^{2-}_{7} \rightarrow Cr^{3+}
  • MnO^{-}_{4} \rightarrow Mn^{2+}
3 0
3 years ago
in order to find the molar mass of an unknown compound, a research scientist prepared a solution of 0.930 g of an unknown in 125
PtichkaEL [24]

Answer:

Molar mass→ 0.930 g / 6.45×10⁻³ mol = 144.15 g/mol

Explanation:

Let's apply the formula for freezing point depression:

ΔT = Kf . m

ΔT = 74.2°C - 73.4°C → 0.8°C

Difference between the freezing T° of pure solvent and freezing T° of solution

Kf = Cryoscopic constant → 5.5°C/m

So, if we replace in the formula

ΔT = Kf . m → ΔT / Kf = m

0.8°C / 5.5 m/°C = m → 0.0516 mol/kg

These are the moles in 1 kg of solvent so let's find out the moles in our mass of solvent which is 0.125 kg

0.0516 mol/kg . 0.125 kg = 6.45×10⁻³ moles. Now we can determine the molar mass:

Molar mass (mol/kg) → 0.930 g / 6.45×10⁻³ mol = 144.15 g/mol

3 0
3 years ago
Which equation agrees with ideal gas law?
Julli [10]
Https://www.gstatic.com/education/formulas2/355397047/en/boyle_s_law.svg
8 0
2 years ago
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