All categories

2 years ago

Why is a solution of 4% acetic acid in 95% ethanol used to wash the crude aldol-dehydration product?

1 answer:

5 0

A cold acetic acid solution is used to wash the residue of the reagent in preparation of an aldol condensation product after vacuum filtration. The main reason in washing with the acetic acid rinse is to neutralize any sodium hydroxide.

You might be interested in

The bowling ball is whizzing down the bowling lane at 4 m/s. If the mass of the bowling ball is 7 kg, what is its kinetic energy

Lisa [10]

Kinetic Energy = 1/2xmassx(velocity)^2
Input values;
K.E=1/2x7kgx(4m/s)^2
K.E.=56J

3 0

2 years ago

Read 2 more answers

Sunlight strikes a piece of crown glass at an angle of incidence of 38.0°. Calculate the difference in the angle of refraction b

zhuklara [117]

Answer:

Difference in the angle of refraction = 0.3°

41.04° is the minimum angle of incidence.

Explanation:

Angle of incidence = 38.0°

For yellow light :

Using Snell's law as:

$\frac {sin\theta_2}{sin\theta_1}=\frac {n_1}{n_2}$

Where,

Θ₁ is the angle of incidence

Θ₂ is the angle of refraction

n₁ is the refractive index for yellow light which is 1.523

n₂ is the refractive index of air which is 1

So,

$\frac {sin\theta_2}{sin{38.0}^0}=\frac {1.523}{1}$

${sin\theta_2}=0.9377$

Angle of refraction for yellow light = sin⁻¹ 0.9377 = 69.67°.

For green light :

Using Snell's law as:

$\frac {sin\theta_2}{sin\theta_1}=\frac {n_1}{n_2}$

Where,

Θ₁ is the angle of incidence

Θ₂ is the angle of refraction

n₁ is the refractive index for green light which is 1.526

n₂ is the refractive index of air which is 1

So,

$\frac {sin\theta_2}{sin{38.0}^0}=\frac {1.526}{1}$

${sin\theta_2}=0.9395$

Angle of refraction for green light = sin⁻¹ 0.9395 = 69.97°.

The difference in the angle of refraction = 69.97° - 69.67° = 0.3°

Calculation of the critical angle for the yellow light for the total internal reflection to occur :

The formula for the critical angle is:

${sin\theta_{critical}}=\frac {n_r}{n_i}$

Where,

${\theta_{critical}}$ is the critical angle

$n_r$ is the refractive index of the refractive medium.

$n_i$ is the refractive index of the incident medium.

n₁ is the refractive index for yellow light which is 1.523 (incident medium)

n₂ is the refractive index of air which is 1 (refractive medium)

Applying in the formula as:

${sin\theta_{critical}}=\frac {1}{1.523}$

The critical angle is = sin⁻¹ 0.6566 = 41.04°

5 0

2 years ago

You ride a roller coaster with a loop-the-loop. Compare the normal force that the seat exerts on you to the force that Earth exe

timofeeve [1]

Answer:

$N = mg + \frac{mv^2}{R}$

Explanation:

At the bottom of the loop, the normal force is opposite to my weight.

I am making a circular motion. So,

$F_{net} = \frac{mv^2}{R}$

The relationship between the normal force, my weight, my speed and the radius of the loop is

$N - mg = \frac{mv^2}{R}\\mg = N - \frac{mv^2}{R}\\ N = mg + \frac{mv^2}{R}$

Here, my weight (mg) is constant. But the normal force is inversely proportional to my speed.

If my speed is zero, the normal force would be maximum and equal to my weight. If my speed is to much, then the normal force would be equally high too.

4 0

2 years ago

An electromagnetic wave is produced by charged particles vibrating at a rate of 3.9 x 10^8 vibrations per second. the electromag

77julia77 [94]

According to sources, the most probable answer to this query is visible light. The speed of light is approximately 3 x 10^8 m/s. This is the part of the electromagnetic spectrum that we can see and perceive. Thank you for your question. Please don't hesitate to ask in Brainly your queries.

7 0

2 years ago

Read 2 more answers

A spring is used to launch a coffee mug. The 20cm long spring can be compressed by a maximum of 8cm. The mug has a mass of 350 g

Zepler [3.9K]

Answer:

7503.13 N/m

Explanation:

Use principle of conservation of energy.

Here, energy stored in the spring due to compression shall be utilized in attaining the potential energy of the mug.

Given that,

Length of the spring = 20 cm = 0.20 m

Compression, x = 8 cm = 0.08 m

mass of the mug, m = 350 g = 0.35 kg

h = 7 m

use the expression for energy balance -

(1/2)*k*x^2 = m*g*h

=> k = (2*m*g*h) / x^2

input the values

k = (2*0.35*9.8*7) / 0.08^2

= 7503.13 N/m

8 0

2 years ago

Read 2 more answers