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Juliette [100K]
3 years ago
13

Identify the number of valence electrons in each atom: a. Calcium b. Carbon c. Sulfur

Chemistry
2 answers:
RoseWind [281]3 years ago
6 0

Answer:

-Sulfur is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S₈. Elemental sulfur is a bright yellow, crystalline solid at room temperature.

(Atomic number: 16

Electron configuration: [Ne] 3s²3p⁴

Electrons per shell: 2,8,6

Electronegativity: 2.58)

-Calcium is the 20th element, with 20 protons. Since a stable atom has a net charge of 0, we must have 20 electrons.

-Carbon is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust.

(Symbol: C

Atomic mass: 12.0107 u

Atomic number: 6

Electrons per shell: 2, 4

Electron configuration: [He] 2s22p2

Electronegativity: 2.55)

Oliga [24]3 years ago
4 0
Look at periodic table and their group number
Calcium - 2
Carbon - 4
Sulfur- 6
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Ammonium perchlorate NH4ClO4 is a powerful solid rocket fuel, used in the Space Shuttle boosters. It decomposes into nitrogen N2
patriot [66]

Answer: 0.055 moles of O_2 are produced by the reaction of 0.055 mol of ammonium perchlorate.

Explanation:

The balanced chemical reaction for decomposition of ammonium perchlorate is:

2NH_4ClO_4\rightarrow N_2+Cl_2+2O_2+4H_2O  

According to stoichiometry :

2 moles of NH_4ClO_4 produce = 2 moles of O_2

Thus 0.055 moles of NH_4ClO_4 will produce =\frac{2}{2}\times 0.055=0.055moles of O_2

Thus 0.055 moles of O_2 are produced by the reaction of 0.055mol of ammonium perchlorate.

7 0
3 years ago
How many moles are in an 11mL solution of NaOh and KHP (C8H4O4)​
zalisa [80]

Answer:

Calculate the molar concentration of the NaOH solution that you prepared Number of moles of KHP = Number of moles NaOH = 2.476 x 10 -3 moles Number of moles NaOH = Mb x Vb Mb = 2.476 x 10 -3 moles / 0.0250 L (equivalence point) = 0.0990 M 3

Explanation:

6 0
3 years ago
What is the primary cause of diffusion? some substances can dissolve in solvents heat added to a substance random internal motio
Nina [5.8K]

Answer:

random internal motion of atoms and molecule

Explanation:

The primary cause of diffusion is the random internal motion of atoms and molecules.

Randomness of atoms and molecules results in diffusion.

  • Diffusion is the movement of particles from a region of high concentration to that of lower concentration.
  • Substances often tend to spread out over the concentration gradient.
  • Therefore, they have this propensity to be randomized.
3 0
3 years ago
how many grams of phosphorus (P4) react with 35.5L of O2 at STP to form solid tetraphosphorus decaoxide
algol [13]

Answer:

mass P4 = 35.998 g

Explanation:

  • P4 + 5O2 → P4O10

∴ STP: P = 1 atm; T = 298 K

∴ V O2= 35.5 L

⇒ nO2 = P.V / R.T

∴ R = 0.082 atm.L/K.mol

⇒ nO2 = ((1 atm)×(35.5L))/((0.082 atm.L/K.mol)(298K))

⇒ nO2 = 1.453 mol O2

⇒ mol P4 = (1.453 molO2)×(mol P4/ 5molO2) = 0.2906 mol P4

∴ Mw P4 = 123.895 g/mol

⇒ mass P4 = (0.2906 mol P4)×(123.895 g/mol) = 35.998 g P4

4 0
3 years ago
At a certain temperature, the vapor pressure of pure benzene ‍ is atm. A solution was prepared by dissolving g of a nondissociat
erastova [34]

Answer:

Molar mass of solute: 300g/mol

Explanation:

<em>Vapor pressure of pure benzene: 0.930 atm</em>

<em>Assuming you dissolve 10.0 g of the non-volatile solute in 78.11g of benzene and vapour pressure of solution was found to be 0.900atm</em>

<em />

It is possible to answer this question based on Raoult's law that states vapor pressure of an ideal solution is equal to mole fraction of the solvent multiplied to pressure of pure solvent:

P_{sln} = X_{solvent}P_{solvent}^0

Moles in 78.11g of benzene are:

78.11g benzene × (1mol / 78.11g) = <em>1 mol benzene</em>

Now, mole fraction replacing in Raoult's law is:

0.900atm / 0.930atm = <em>0.9677 = moles solvent / total moles</em>.

As mole of solvent is 1:

0.9677× total moles = 1 mole benzene.

Total moles:

1.033 total moles. Moles of solute are:

1.033 moles - 1.000 moles = <em>0.0333 moles</em>.

As molar mass is the mass of a substance in 1 mole. Molar mass of the solute is:

10.0g / 0.033moles = <em>300g/mol</em>

8 0
3 years ago
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