Use the periodic to fill in the numbers in the electron configurations shown below

When 231. mg of a certain molecular compound X are dissolved in 65. g of benzene (CH), the freezing point of the solution is mea

Elan Coil [88]

Answer:

Molar mass X = 18.2 g/mol

Explanation:

Step 1: Data given

Mass of compound X = 231 mg = 0.231 grams

Mass of benzene = 65.0 grams

The freezing point of the solution is measured to be 4.5 °C.

Freezing point of pure benzene = 5.5 °C

The freezing point constant for benzene is 5.12 °C/m

Step 2: Calculate molality

ΔT = i*Kf*m

⇒ΔT = the freezing point depression = 5.5 °C - 4.5 °C = 1.0 °C

⇒i = the Van't hoff factor = 1

⇒Kf = the freezing point depression constant for benzene = 5.12 °C/m

⇒m = the molality = moles X / mass benzene

m = 1.0 / 5.12 °C/m

m = 0.1953 molal

Step 3: Calculate moles X

Moles X = molality * mass benzene

Moles X = 0.1953 molal * 0.065 kg

Moles X = 0.0127 moles

Step 4: Calculate molar mass X

Molar mass X = mass / moles

Molar mass X = 0.231 grams / 0.0127 moles

Molar mass X = 18.2 g/mol

5 0

3 years ago

What part of the digestive system removes most of the water from food?

satela [25.4K]

Large intestines hgtgfjcob turn o bff 15th t ? vc

3 0

3 years ago

What is the molarity of a solution made by adding 0.720 mole of NaOH to 2.40 liters of water

WITCHER [35]

Answer:

Molarity = 0.3 M

Explanation:

Given data:

Moles of NaOH = 0.720 mol

Volume of water = 2.40 L

Molarity = ?

Solution:

Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.

Formula:

Molarity = number of moles of solute / L of solution

Molarity = 0.720 mol / 2.40 L

Molarity = 0.3 mol/L

Molarity = 0.3 M

7 0

3 years ago

In an aqueous solution of a certain acid the acid is 4.4% dissociated and the pH is 3.03. Calculate the acid dissociation consta

NeX [460]

Answer:

4.1x10⁻⁵

Explanation:

The dissociation of an acid is a reversible reaction, and, because of that, it has an equilibrium constant, Ka. For a generic acid (HA), the dissociation happens by:

HA ⇄ H⁺ + A⁻

So, if x moles of the acid dissociates, x moles of H⁺ and x moles of A⁻ is formed. the percent of dissociation of the acid is:

% = (dissociated/total)*100%

4.4% = (x/[HA])*100%

But x = [A⁻], so:

[A⁻]/[HA] = 0.044

The pH of the acid can be calcualted by the Handersson-Halsebach equation:

pH = pKa + log[A⁻]/[HA]

3.03 = pKa + log 0.044

pKa = 3.03 - log 0.044

pKa = 4.39

pKa = -logKa

logKa = -pKa

Ka = $10^{-pKa}$

Ka = $10^{-4.39}$

Ka = 4.1x10⁻⁵

4 0

3 years ago

If the chemical properties of a substance remain unchanged and the appearance or shape of an substance changes it is called a

vladimir1956 [14]

Answer:

Physical change

Explanation:

Physical change -

It is the type of reversible change , where there is change in the state of the matter , is referred to as a physical change .

There is no chemical process involved during state change , i.e. , no new substance is formed .

Hence , from the given statement of the question, the correct term is physical change.

3 0

2 years ago