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Elodia [21]
3 years ago
7

Which statement about the periodic table is true?

Chemistry
1 answer:
dedylja [7]3 years ago
8 0

Answer

Two different elements have similar chemical properties when they have the same number of valence electrons in their outermost energy level. ... Elements in the same column of the Periodic Table have the same number of valence electrons – that's why they have similar chemical properties.

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There is an error in the rate-determining step of the following proposed mechanism.
yulyashka [42]

Answer:

The steps with correct mechanism are given below:

C

1) CH₄(g) + Cl(g) → CH₃(g) + HCl(g) : This is a slow step.

The rate is given as: R1 = k₁[CH₄][Cl]  

2) CH₃(g) + Cl₂(g) → CH₃Cl(g) + Cl(g): This is a fast step.

The rate is given as: Rate = k₂[CH₃][Cl₂]  

∴ CH₄(g) + Cl₂(g) → CH₃Cl(g) + HCl(g)

Here, the slowest step will be the rate-determining step.

5 0
3 years ago
What are the 4 major macromolecules
ANEK [815]
Carbohydrates
Lipids
Protein
Nucleic acids
8 0
3 years ago
Which process is characterized by the movement of particles?.
Serjik [45]

Answer: Diffusion is the movement of particles from a high to low particle concentration, while osmosis is the movement of water from a high to a low water concentration.

Explanation:

6 0
3 years ago
Read 2 more answers
What are the molality and mole fraction of solute in a 22.3 percent by mass aqueous solution of formic acid (HCOOH)?
Vanyuwa [196]

Answer:

Mole fraction for solute = 0.1, or 10%

Molality = 6.24 mol/kg

Explanation:

22.3% by mass → In 100 g of solution, we have  22.3 g of HCOOH

Mass of solution = 100 g

Mass of solute = 22.3 g

Mass of solvent = 100 g - 22.3g = 77.7 g

Let's convert the mass to moles

22.3 g . 1mol/ 46 g = 0.485 moles

77.7 g. 1mol / 18 g = 4.32 moles

Total moles = 4.32 moles + 0.485 moles = 4.805 moles

Xm for solute = 0.485 / 4.805 = 0.100 → 10%

Molality → mol/ kg → we convert the mass of solvent to kg

77.7 g.  1 kg / 1000g = 0.0777 kg

0.485 mol / 0.0777 kg = 6.24 m

6 0
3 years ago
Read 2 more answers
If aluminum is diffused into a thick slice of silicon with no previous aluminum in it at a temperature of 1100˚C for 8 hours, wh
RideAnS [48]

Answer:

8.354 nanometers

Explanation:

To treat a diffusive process in function of time and distance we need to solve  2nd Ficks Law. This a partial differential equation, with certain condition the solution looks like this:

\frac{C_{s}-C{x}}{C_{s}-C_{o}}=erf(x/2\sqrt{D*t})

Where Cs is the concentration in the surface of the solid

Cx is the concentration at certain deep X

Co is the initial concentration of solute in the solid

and erf is the error function

Then we solve right side,

\frac{C_{s}-C{x}}{C_{s}-C_{o}}=\frac{1018atoms/cm3-1016atoms/cm3}{1018atoms/cm3}=0.001964

And we need to look up the inverse error function of 0.001964 resulting in: 0.00174055

Then we solve for x:

x=0.00174055*2*\sqrt{D*t} =0.00174055*2*\sqrt{2*10^{-12}cm^{2}/s*8h*3600s/h}=8.35464*10^{-7}cm

6 0
3 years ago
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