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3 years ago

Write reaction showing how each of the buffers would neutralize added naoh. hcho2 and nacho2

1 answer:

3 0

<span>The acid-base neutralization reaction between formic acid (HCHO2) and sodium hydroxide (NaOH) is

HCHO2(aq) + NaOH(s) --> NaCHO2(aq) + H2O(l)

Formic acid is a weak acid. So, the salt formed here is a basic salt, NaCHO2 or Sodium Formate. A buffer solution is when the system contains either a weak acid and its conjugate strong base or a weak base and its conjugate strong acid. In this case, formic acid is the weak base, while sodium formate is the conjugate strong base. So, this is a buffer system. By definition, a buffer resists pH changes with small addition of either a base or an acid. So, when NaOH is added, it would produce more of sodium formate. As long as formic acid is not depleted, the buffer system would be stable.</span>

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Which is NOT a phase of mitosis?

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Toluene (C6H5CH3 ), an organic compound often used as a solvent in paints, is mixed with a similar organic compound, benzene (C6

Sergeeva-Olga [200]

Explanation:

The given data is as follows.

Weight of solute = 75.8 g, Molecular weight of solute (toulene) = 92.13 g/mol, volume = 200 ml

Therefore, molarity of toulene is calculated as follows.

Molarity = $\frac{\text{weight of solute}}{\text{molecular weight of solute}} \times \frac{1000}{\text{volume of solution in ml}}$

= $\frac{75.8 g}{92.13 g/mol} \times \frac{1000}{200 ml}$

= 4.11 M

Hence, molarity of toulene is 4.11 M.

As molality is the number of moles of solute present in kg of solvent.

So, we will calculate the molality of toulene as follows.

Molality = $\frac{\text{given weight of solute}}{\text{given molecular weight of solute}} \times \frac{1000}{\text{weight of solvent in grams}}$

= $\frac{75.8 g}{92.13 g/mol} \times \frac{1000}{95.6 g}$

= 8.6 m

Hence, molality of given toulene solution is 8.6 m.

Now, calculate the number of moles of toulene as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{75.8 g}{92.13 g/mol}$

= 0.8227 mol

Now, no. of moles of benzene will be as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{95.6 g}{78.11 g/mol}$

= 1.2239 mol

Hence, the mole fraction of toulene is as follows.

Mole fraction = $\frac{\text{moles of toulene}}{\text{total moles}}$

= $\frac{0.8227 mol}{(0.8227 + 1.2239) mol}$

= 0.402

Hence, mole fraction of toulene is 0.402.

As density of given solution is 0.857 $g/cm^{3}$ so, we will calculate the mass of solution as follows.

Density = $\frac{mass}{volume}$

0.857 $g/cm^{3}$ = $\frac{mass}{200 ml}$ (As 1 $cm^{3}$ = 1 g)

mass = 171.4 g

Therefore, calculate the mass percent of toulene as follows.

Mass % = $\frac{\text{mass of solute}}{\text{mass of solution}} \times 100$

= $\frac{75.8 g}{171.4 g} \times 100$

= 44.22%

Therefore, mass percent of toulene is 44.22%.

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3 years ago

I what process does a solid change directly into a vapor

Marina86 [1]

Answer:

solid change directly into a vapor in the process known simply as freezing

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Mkey [24]

The mass change, or the mass defect, can be calculated by the formula that is very known to be associated with Albert Einstein.

E = Δmc²
where
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c is the speed of light equal to 3×10⁸ m/s
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3 years ago

Determine if these molecules and ion are polar.

Colt1911 [192]

Answer:

a. Polar

b. Polar

c. Non-polar

d. Non-polar

Explanation:

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b. $H_2S$ has the same shape as water. There are two lone pairs on sulfur atom which produce an overall dipole moment in this molecule, the bent structure is polar.

c. $PCl_5$ is non-polar, as the central atom, phosphorus, doesn't contain any lone pairs, all the dipole moments cancel out: two dipole moments in the vertical plane, P-Cl, and three P-Cl dipoles in the horizontal plane within a trigonal bipyramidal shape.

d. $CF_4$ is non-polar, since it's a tetrahedral molecule with no lone pairs on carbon atom, all four C-F dipole moments cancel out to yield a net 0 dipole moment.

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