Pentanone, because it will boil at around 100 to 102 degree C, about the same as water, while propane boils at about -42 degree C, a temperature way below both pentanone and water's freezing point.

6 0

3 years ago

Calculate the final pH of a solution made by the addition of 10 mL of a 0.5 M NaOH solution to 500 mL of a 0.4 M HA originally a

Allushta [10]

This question is not complete, the complete question is;

Calculate the final pH of a solution made by the addition of 10 mL of a 0.5 M NaOH solution to 500 mL of a 0.4 M HA originally at pH = 5.0 ( pKa = 5.0)

Neglect the volume change.

Options:

a) 6.10

b) 5.09

c) 7.00

d) 5.02

Answer:

the final pH of a solution is 5.02

Option d) 5.02 is the Correct Answer

Explanation:

Given the data in the question,

Initially pKa = pH; so ratio is 1:1

thus, 0.4 M acid and base

Now, moles of NaOH = molarity × volume = 0.5 × 10 = 5 mmol = 5 × 10⁻³ mol.

Going into 500 mL ( 0.5 L ) of solution

new molarity will be;

⇒ moles / volume = 5 × 10⁻³ / 0.5 = 0.01 M

ACID reacting with BASE

original concentration of acid = 0.4 - 0.01 = 0.39 M

original concentration of base = 0.4 + 0.01 = 0.41 M

pH = 5 + log( base/acid)

= 5 + log ( 0.41/0.39)

= 5 + log ( 1.0512)

= 5 + 0.021

pH = 5.02

Therefore the final pH of a solution is 5.02

Option d) 5.02 is the Correct Answer

5 0

3 years ago

How many molecules are in 20.0 L(liters) of SO2 at STP

Finger [1]

5.4 x 10²³ molecules

Explanation:

Given parameter

Volume of gas = 20L

Condition of reaction = STP

Unknown:

number of molecules

Solution:

The number of molecules of a substance is given by;

Number of molecules = Number of moles x avogadro's constant

Number of moles at stp = $\frac{volume of gas}{22.4}$

Number of moles of SO₂ = $\frac{20}{22.4}$ = 0.893mole

Number of molecules = 0.893 x 6.02 x 10²³ = 5.4 x 10²³ molecules

learn more:

Number of molecules brainly.com/question/10818009

#learnwithBrainly

4 0

3 years ago