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3 years ago

Which element above has 6 protons in its nucleus?

Chemistry

2 answers:

Vinil7 [7]3 years ago

5 0

B. carbon because it's atomic number is 6

WITCHER [35]3 years ago

5 0

Answer:

the answer is b

Explanation:

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Which of these shows a volume of 1.25 liters expressed in milliliters

stellarik [79]

I would use a conversation calculator

3 0

3 years ago

Read 2 more answers

What is the percent of Cr in Cr2O3

IgorLugansk [536]

The percentage of Chromium in Chromium Oxide is calculated as follow,

Step 1:
Calculate Molar mass of Cr₂O₃,
Cr = 51.99 u
O = 16 u
So,
2(51.99) + 3(16) = 103.98 + 48 = 151.98 u

Step 2:
Secondly divide molar mass of only chromium with total mass of Cr₂O₃ and multiply with 100.
i.e.
= $\frac{103.98}{151.98}$ × 100

= 68.41 %
So, the %age composition of chromium in chromium oxide is 68.41 %.

5 0

3 years ago

Read 2 more answers

Which of the Atoms shown has an atomic number four

dimulka [17.4K]

Answer:

Explanation:

Atomic # = Protons

it says 4 p in the inside of the orbital

4 0

3 years ago

(3) A 10.00-mL sample of 0.1000 M KH2PO4 was titrated with 0.1000 M HCl Ka for phosphoric acid (H3PO4): Ka1= 7.50x10-3; Ka2=6.20

shtirl [24]

Answer:

The pH of this solution is 1,350

Explanation:

The phosphoric acid (H₃PO₄) has three acid dissociation constants:

HPO₄²⁻ ⇄ PO4³⁻ + H⁺ Kₐ₃ = 4,20x10⁻¹⁰ (1)

H₂PO₄⁻ ⇄ HPO4²⁻ + H⁺ Kₐ₂ = 6,20x10⁻⁸ (2)

H₃PO₄ ⇄ H₂PO4⁻ + H⁺ Kₐ₁ = 7,50x10⁻³ (3)

The problem says that you have 10,00 mL of KH₂PO₄ (It means H₂PO₄⁻) 0,1000 M and you add 10,00 mL of HCl (Source of H⁺) 0,1000 M. So you can see that we have the reactives of the equation (3).

We need to know what is the concentration of H⁺ for calculate the pH.

The moles of H₂PO₄⁻ are:

10,00 mL × ( 1x10⁻⁴ mol / mL) = 1x10⁻³ mol

The moles of H⁺ are, in the same way:

10,00 mL × ( 1x10⁻⁴ mol / mL) = 1x10⁻³ mol

So:

H₃PO₄ ⇄ H₂PO4⁻ + H⁺ Kₐ₁ = 7,50x10⁻³ (3)

X mol ⇄ (1x10⁻³-X) mol + (1x10⁻³-X) mol (4)

The chemical equilibrium equation is:

Kₐ₁ = ([H₂PO4⁻] × [H⁺] / [H₃PO₄]

So:

7,50x10⁻³ = (1x10⁻³-X)² / X

Solving the equation you will obtain:

X² - 9,5x10⁻³ X + 1x10⁻⁶ = 0

Solving the quadratic formula you obtain two roots:

X = 9,393x10⁻³ ⇒ This one has no chemical logic because solving (4) you will obtain negative H₂PO4⁻ and H⁺ moles

X = 1,065x10⁻⁴

So the moles of H⁺ are : 1x10⁻³- 1,065x10⁻⁴ : 8,935x10⁻⁴ mol

The reaction volume are 20,00 mL (10,00 from both KH₂PO₄ and HCL)

Thus, the molarity of H⁺ ([H⁺]) is: 8,935x10⁻⁴ mol / 0,02000 L = 4,468x10⁻² M

pH is -log [H⁺]. So the obtained pH is 1,350

I hope it helps!

5 0

2 years ago

What is the intermolecular force of NH3

Dominik [7]

ANSWER:
London dispersion and hydrogen bonds.

EXPLANATION :
Every molecule experiences London dispersion as an intermolecular force.since the ammonia ion has hydrogen atoms bonded to nitrogen,a very electronegative atom,the molecule is also polar since the nitrogen atom more strongly pulls on the electrons from the hydrogen atoms than the hydrogens themselves do.

This effect is similar to that water,where the oxygen pulls the electrons of the hydrogen atoms with a greater magnitude,resulting in the oxygen having a partial negative charge and the hydrogens having a partial positive charge relative to each other.

This polarity shows that the molecule has dipole-dipole intermolecular forces but since the polarity is from a result of highly electronegative atoms (such as nitrogen,oxygen,fluorine) and hydrogen atoms actually bonded to them,the polarity is categorized in it's own intermolecular force called a hydrogen bond.

I HOPE IT HELPS:)

3 0

3 years ago