What is the trend in electropositivity in group 1 elements?

4. What is the total mass of ice that can be vaporized by 2100 kJ of heat energy?

anygoal [31]

Answer:

5 g

Explanation:

The heat required to vaporize ice is the sum of

i) Heat required to melt ice at 0°C

ii) Heat required to raise the temperature from 0°C to 100°C

iii) Heat required to vaporize water at 100°C

Thus;

H = nLfus + ncθ + nLvap

H= n(Lfus + cθ + Lvap)

Lfus = 6.01 kJ/mol

Lvap = 41 kJ/mol

c = 75.38

n =?

2100 = n(6.01 + 75.38(100) + 41)

n = 2100 KJ/7585.01 kJ/mol

n = 0.277 moles

Mass of water = number of moles * molar mass

Mass of water = 0.277 moles * 18 g/mol

Mass of water = 5 g

3 0

3 years ago

Consider the following reaction: A(g)⇌2B(g). Find the equilibrium partial pressures of A and B for each of the following differe

Illusion [34]

Answer:

a. Kp=1.4

$P_{A}=0.2215 atm$

$P_{B}=0.556 atm$

b.Kp=2.0 * 10^-4

$P_{A}=0.495atm$

$P_{B}=0.00995 atm$

c.Kp=2.0 * 10^5

$P_{A}=5*10^{-6}atm$

$P_{B}=0.9999 atm$

Explanation:

For the reaction

A(g)⇌2B(g)

Kp is defined as:

$Kp=\frac{(P_{B})^{2}}{P_{A}}$

The conditions in the system are:

A B

initial 0 1 atm

equilibrium x 1atm-2x

At the beginning, we don’t have any A in the system, so B starts to react to produce A until the system reaches the equilibrium producing x amount of A. From the stoichiometric relationship in the reaction we get that to produce x amount of A we need to 2x amount of B so in the equilibrium we will have 1 atm – 2x of B, as it is showed in the table.

Replacing these values in the expression for Kp we get:

$Kp=\frac{(1-2x)^{2}}{x}$

Working with this equation:

$x*Kp=(1-2x)^{2} - -> x*Kp=4x^{2}-4x+1- - >4x^{2}-(4+Kp)*x+1=0$

This last expression is quadratic expression with a=4, b=-(4+Kp) and c=1

The general expression to solve these kinds of equations is:

$x=\frac{-b(+-)*\sqrt{(b^{2}-4ac)}}{2a}$ (equation 1)

We just take the positive values from the solution since negative partial pressures don´t make physical sense.

Kp = 1.4

$x_{1}=\frac{(1.4+4)+\sqrt{(-(1.4+4)^{2}-4*4*1)}}{2*4}=1.128$

$x_{1}=\frac{(1.4+4)-\sqrt{(-(1.4+4)^{2}-4*4*1)}}{2*4}=0.2215$

With x1 we get a partial pressure of:

$P_{A}=1.128 atm$

$P_{B}=1-2*1.128 = -1.256 atm$

Since negative partial pressure don´t make physical sense x1 is not the solution for the system.

With x2 we get:

$P_{A}=0.2215 atm$

$P_{B}=1-2*0.2215 = 0.556 atm$

These partial pressures make sense so x2 is the solution for the equation.

We follow the same analysis for the other values of Kp.

Kp=2*10^-4

X1=0.505

X2=0.495

With x1

$P_{A}=0.505atm$

$P_{B}=1-2*0.505 = -0.01005 atm$

Not sense.

With x2

$P_{A}=0.495atm$

$P_{B}=1-2*0.495 = 0.00995 atm$

X2 is the solution for this equation.

Kp=2*10^5

X1=50001

$X2=5*10^{-6}$

With x1

$P_{A}=50001atm$

$P_{B}=1-2*50001=-100001atm$

Not sense.

With x2

$P_{A}= 5*10^{-6}atm$

$P_{B}=1-2*5*10^{-6}= 0.9999 atm$

X2 is the solution for this equation.

8 0

3 years ago

????.? .?.? . I have some question on Alef website

Andrew [12]

B. crust, middle, core

8 0

3 years ago

Read 2 more answers

What direction do the plates have to move in order for an earthquake to occur?

Bess [88]

they would be pushing together

4 0

3 years ago

Read 2 more answers

In models of molecules, spheres of different colors and

AlladinOne [14]

Answer:

D

Explanation:

According to this question, each model of molecules in the options contains spheres of different colors and sizes representing different types of atoms. The atoms of the same element are the spheres of same color and size while atoms of different element are of different color or size.

Therefore, the model showing a molecule of a substance that is made up of three elements is model D because it is made up of three distinct spheres representing atoms of each element.

- The red sphere is the atom of the first element

- The big dark sphere is the atom of the second element

- The small white sphere is the atom of the third element

3 0

3 years ago

What is the trend in electropositivity in group 1 elements?​

What is the trend in electropositivity in group 1 elements?