Hi! Which of the following decreases kinetic energy of solvent molecules? ( I need this handed in quickly!)

A 10.0 g sample of an unknown liquid is vaporized at 120.0°C and 5.0 atm. The volume of the vapour is found to be 568.0 mL. The

Naya [18.7K]

Answer:

C8H16

Explanation:

First thing to do here is to calculate the molar mass of the compound

Mathematically;

molar mass = mass/number of moles

we can calculate the number of moles using the ideal gas equation

Mathematically;

PV = nRT

n = PV/RT

where p is the pressure at 5 atm

V is the volume at 568 ml = 568/1000 = 0.568 L

R is the molar gas constant which is 0.0821

T is the temperature which is 120+ 273 = 393k

Inserting these values into the equation, we have

n = (5 * 0.568)/(0.0821 * 393)

n = 0.088 moles

So the molar mass = 10/0.088

= 114 g/mol

Now let’s go to the percentages

C = 84.2/12 = 7.016666666666667

H = 15.8/1 = 15.8

divide by the smallest

C = 7.016666666666667/7.016666666666667 = 1

H = 15.8/7.016666666666667 = 2 approximately

The empirical formula is CH2

So for the molecular formula, we have;

(12 + 2)n = 114

14n = 114

n = 114/14 = approximately 8

So the molecular formula of the liquid will be (CH2)n = C8H16

3 0

3 years ago

3. A representation of one unit of KCl in water is shown below. (The water molecules are intentionally not shown.)

alukav5142 [94]

The representation is showing potassium atom (K) and Chlorine atom (Cl) when it ought to show their ions i.e potassium ion (K⁺) and Chlorine ion (Cl¯)

<h3>Dissociation equation for KCl</h3>

When potassium chloride, KCl dissolves in water, it dissociate to produce potassium ion (K⁺) and Chlorine ion (Cl¯) as shown below:

KCl(aq) —> K⁺(aq) + Cl¯(aq)

The representation given in the question is only showing potassium atom (K) and Chlorine atom (Cl). This makes it wrong as dissolution of ionic compounds in water will results in the corresponding ions of the element that makes up the compound