1What is one major difference between fossil fuels and biofuels?

Pyridine (c5h5n) is a particularly foul-smelling substance used in manufacturing pesticides and plastic resins. calculate the ph

zubka84 [21]

Answer is: ph value of pyridine solution is 9.1.

Chemical reaction: C₅H₅N + H₂O → C₅H₅NH⁺ + OH⁻.
c(pyridine - C₅H₅N) = 0.115M.
Kb(C₅H₅N) = 1.4·10⁻⁹.
[C₅H₅NH⁺] = [OH⁻] = x; equilibrium concentration.
[C₅H₅N] = 0.115 M - x.

Kb = [C₅H₅NH⁺] · [OH⁻] / [C₅H₅N].

1.4·10⁻⁹ = x² / (0.115 M -x)

Solve quadratic equation: x = [OH⁻] = 0.0000127 M.
pOH = -log(0.0000127 M) = 4.9

pH = 14 - 4.9 = 9.1.

7 0

3 years ago

How many moles are in 20 grams of argon

Sladkaya [172]

Answer:

There are 0.5 mole in 20g of argon.

Explanation:

40 g of argon = 1mole

Then 20g of argon is,

→ 1/40 × 20

→ 0.5 mole

5 0

3 years ago

If a sample of gas is located 10.2 cm from the injection point and the chart speed is 0.5 cm/min, what is the retention time?

Archy [21]

Answer : The retention time is, 20 min

Explanation :

Retention time : It is defined as the amount of time a compound spends on the column after it has been injected.

Formula of retention time is:

$\text{Retention time}=\frac{\text{Distance from injection point to center of peaks}}{\text{Chart recorded speed}}$

Given:

Distance from injection point to center of peaks = 10 cm

Chart recorded speed = 0.5 cm/min

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

$\text{Retention time}=\frac{10cm}{0.5cm/min}$

Retention time = 20 min

Thus, the retention time is, 20 min

3 0

4 years ago

0.250 moles of NaCl is dissolved in 0.850 L of solution. What is the molar concentration?

Nuetrik [128]

Considering the definition of molarity, the molar concentration is 0.294 $\frac{moles}{liter}$ .

Molarity reflects the concentration of a solution indicating the number of moles of solute that are dissolved in a given volume.

The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:

$molarity=\frac{amount of moles of solute}{volume}$

Molarity is expressed in units $\frac{moles}{liter}$ .

In this case, you know:

amount of moles of solute= 0.250 moles
volume= 0.850 L

Replacing in the definition of molarity:

$molarity=\frac{0.250 moles}{0.850 L}$

Solving:

molarity= 0.294 $\frac{moles}{liter}$

Finally, the molar concentration is 0.294 $\frac{moles}{liter}$ .

Learn more about molarity with this example: brainly.com/question/15406534?referrer=searchResults

6 0

3 years ago

Three mixtures were prepared from three very narrow molar mass distribution polystyrene samples with molar masses of 10,000, 30,

8_murik_8 [283]

Answer:

(a). 46,666.7 g/mol; 78,571.4 g/mol

(b). 86950g/mol; 46,666.7 g/mol.

(c). 86950g/mol; 43,333.33 g/mol

Explanation:

So, we are given the molar masses for the three samples as: 10,000, 30,000 and 100,000 g mol−1.

Thus, the equal number of molecule in each sample = ( 10,000 + 30,000 + 100,000 ) / 3 = 46,666.7 g/mol.

The average molar mass = [ ( 10,000)^2 + (30,000)^2 + 100,000)^2] ÷ 10,000 + 30,000 + 100,000 = 78,571. 4 g/mol.

(b). The equal masses of each sample = 3/[ ( 1/ 10,000) + (1/30,000 ) + (1/100,000) ] = 20930.23 g/mol.

Average molar mass = ( 10,000 + 30,000 + 100,000 ) / 3 = 46,666.7 g/mol.

(c). Equal masses of the two samples = (0.145 × 10,000) + (0.855 × 100,000)/ 0.145 + 0.855 = 86950g/mol.

The weight average molar mass = 1.7 + 10,000 + 100,000/ 1.7 + 1 = 43,333.33 g/mol.

6 0

3 years ago