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spayn [35]
3 years ago
14

Josie draws models of the particles within a substance. Which model best represents the particles in

Chemistry
1 answer:
Pachacha [2.7K]3 years ago
5 0
D I'm pretty sure...........
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What would be the formula for diphosphorus pentoxide ?
aleksley [76]
PbCr04 + P4O10

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3 0
3 years ago
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determine the ph of a buffer that is 0.55 M HNO2 and 0.75 M KNO2. tha value of Ka for HNO2 is 6.8*10^-4
Mariana [72]

Answer:

pH = 3.3

Explanation:

Buffer solutions minimize changes in pH when quantities of acid or base are added into the mix. The typical buffer composition is a weak electrolyte (wk acid or weak base) plus the salt of the weak electrolyte. On addition of acid or base to the buffer solution, the solution chemistry functions to remove the acid or base by reacting with the components of the buffer to shift the equilibrium of the weak electrolyte left or right to remove the excess hydronium ions or hydroxide ions is a way that results in very little change in pH of the system. One should note that buffer solutions do not prevent changes in pH but minimize changes in pH. If enough acid or base is added the buffer chemistry can be destroyed.

In this problem, the weak electrolyte is HNO₂(aq) and the salt is KNO₂(aq). In equation, the buffer solution is 0.55M HNO₂ ⇄ H⁺ + 0.75M KNO₂⁻ . The potassium ion is a spectator ion and does not enter into determination of the pH of the solution. The object is to determine the hydronium ion concentration (H⁺) and apply to the expression pH = -log[H⁺].

Solution using the I.C.E. table:

              HNO₂ ⇄    H⁺   +   KNO₂⁻

C(i)        0.55M       0M      0.75M

ΔC            -x            +x          +x

C(eq)  0.55M - x       x     0.75M + x    b/c [HNO₂] / Ka > 100, the x can be                                    

                                                             dropped giving ...

           ≅0.55M        x       ≅0.75M        

Ka = [H⁺][NO₂⁻]/[HNO₂] => [H⁺] = Ka · [HNO₂]/[NO₂⁻]

=> [H⁺] = 6.80x010⁻⁴(0.55) / (0.75) = 4.99 x 10⁻⁴M

pH = -log[H⁺] = -log(4.99 x 10⁻⁴) -(-3.3) = 3.3

Solution using the Henderson-Hasselbalch Equation:

pH = pKa + log[Base]/[Acid] = -log(Ka) + log[Base]/[Acid]

= -log(6.8 x 10⁻⁴) + log[(0.75M)/(0.55M)]

= -(-3.17) + 0.14 = 3.17 + 0.14 = 3.31 ≅ 3.3

3 0
3 years ago
calculate the number of moles of sulfuric acid that is contained in 250 mL of 8.500 M sulfuric acid solution
san4es73 [151]

Answer : The moles of H_2SO_4 are, 2.125 mole.

Explanation : Given,

Molarity of H_2SO_4 = 8.500 M

Volume of solution = 250 mL  = 0.250 L    (1 L = 1000 mL)

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

\text{Molarity}=\frac{\text{Moles of }H_2SO_4}{\text{Volume of solution (in L)}}

Now put all the given values in this formula, we get:

8.500M=\frac{\text{Moles of }H_2SO_4}{0.250L}

\text{Moles of }H_2SO_4=2.125mol

Therefore, the moles of H_2SO_4 are, 2.125 mole.

5 0
3 years ago
If 21.3 grams of lithium react with excess water, how many liters of hydrogen gas can be produced at 297 Kelvin and 1.40 atmosph
Gnoma [55]
Hope it helped you.

4 0
3 years ago
How does a network solid differ from most other covalent compounds
blondinia [14]

Answer:

Covalent compounds are held by intermolecular forces while network solids are held by strong bonds in unit cells which are closely packed together.

Explanation:

Covalent compound molecules are held by vanderwaals forces which are relatively weak but strong enough to hold some covalent molecules together in the solid state. However, network solids contain atom to atom covalent bonds arranged in an orderly manner and regular repeating unit cells to form a rigid three dimensional network solid.

5 0
3 years ago
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