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3 years ago

Can someone help.? thanks :)

Chemistry

1 answer:

laila [671]3 years ago

4 0

Answer:

1. Equation: 2x + 3 = 9x - 11

2. Each row has 2 chairs

Explanation:

The variable x represents the number of chairs in each row.

1. She can form 2 rows of a given length with 3 chairs left over.

Thus, she has:

number of rows number of chairs in chairs number of chairs

each row left over she has

2 x 3 2x + 3

2. She can form 9 rows of the same length if she gets 11 more chairs.

That means that she is short in 11 chairs to have 9x chairs, or that she has 11 less chairs than 9x chairs. Then she has:

9x - 11

3. Equation:

Then, number of chairs she has is 2x + 3 and, also, 9x - 11, which allows to set the equation:

2x + 3 = 9x -11

4. Solve the equation:

9x - 2x = 3 + 11

7x = 14

x = 2

Therefore, each row has 2 chairs, and she has 2x + 3 = 4 + 3 = 7 chairs.

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The estimated heat of vaporization of diethyl ether using the Chen's rule is A. 29.7 KJ/mol B. 33.5 KJ/mol C. 26.4 KJ/mol D. 36.

Brums [2.3K]

Answer:

C. 26.4 kJ/mol

Explanation:

The Chen's rule for the calculation of heat of vaporization is shown below:

$\Delta H_v=RT_b\left [ \frac{3.974\left ( \frac{T_b}{T_c} \right )-3.958+1.555lnP_c}{1.07-\left ( \frac{T_b}{T_c} \right )} \right ]$

Where,

$\Delta H_v$ is the Heat of vaoprization (J/mol)

$T_b$ is the normal boiling point of the gas (K)

$T_c$ is the Critical temperature of the gas (K)

$P_c$ is the Critical pressure of the gas (bar)

R is the gas constant (8.314 J/Kmol)

For diethyl ether:

$T_b=307.4\ K$

$T_c=466.7\ K$

$P_c=36.4\ bar$

Applying the above equation to find heat of vaporization as:

$\Delta H_v=8.314\times307.4 \left [ \frac{3.974\left ( \frac{307.4}{466.7} \right )-3.958+1.555ln36.4}{1.07-\left ( \frac{307.4}{466.7} \right )} \right ]$

$\Delta H_v=26400 J/mol$

The conversion of J into kJ is shown below:

1 J = 10⁻³ kJ

Thus,

$\Delta H_v=26.4 kJ/mol$

Option C is correct

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Please find the structure attached as an image

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Can someone help.? thanks :)​

Can someone help.? thanks :)