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Svetllana [295]

3 years ago

11

Sunspots appear dark because they are what ?

1 answer:

dsp733 years ago

3 0

Sunspots have strong magnetic fields, thus being much cooler than their surroundings. Yet, they are still individually very hot and can reach up to a temp of 3,800 K. But since they are cooler than their surroundings, they appear to be much darker to the visible eye.

Let me know if you need anything further. :)

- Dotz

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Since the action and reaction are exactly equal and oppositely directed , how can there be a net force on an object ?

erma4kov [3.2K]

Answer: Net force is the summation of all the forces involved or acting on an object.

Explanation: For action and reaction situation it states that the Fa = -Fb. Both forces with equal magnitudes but opposite direction will cancel out each other having a zero net force.

6 0

3 years ago

a chemist wishes to mix some pure acid with some water to produce 16L of a solution that is 30% acid how much pure acid and how

Aloiza [94]

<u>Answer:</u> The volume of acid and water that must be mixed will be 4.8 L and 11.2 L

<u>Explanation:</u>

We are given:

Volume of mixture = 16 L

Percent of acid present = 30 %

Calculating the percentage of acid present in the mixture:

$\Rightarrow 16\times \frac{30}{100}=4.8L$

The mixture is made entirely of acid and water.

Volume of acid in the mixture = 4.8 L

Volume of water in the mixture = 16 - 4.8 = 11.2 L

Hence, the volume of acid and water that must be mixed will be 4.8 L and 11.2 L

4 0

3 years ago

In a room full of air, the air is mainly composed of Nitrogen and Oxygen molecules (both at room temperature). Find (to two sign

zloy xaker [14]

Explanation:

Expression for the $v_{rms}$ speed is as follows.

$v_{rms} = \sqrt{\frac{3kT}{M}}$

where, $v_{rms}$ = root mean square speed

k = Boltzmann constant

T = temperature

M = molecular mass

As the molecular weight of oxygen is 0.031 kg/mol and R = 8.314 J/mol K. Hence, we will calculate the value of $v_{rms}$ as follows.

$v_{rms} = \sqrt{\frac{3kT}{M}}$

= $\sqrt{\frac{3 \times 8.314 J/mol K \times 309.02 K}{0.031 kg/mol}}$

= 498.5 m/s

Hence, $v_{rms}$ for oxygen atom is 498.5 m/s.

For nitrogen atom, the molecular weight is 0.028 kg/mol. Hence, we will calculate its $v_{rms}$ speed as follows.

$v_{rms} = \sqrt{\frac{3kT}{M}}$

= $\sqrt{\frac{3 \times 8.314 J/mol K \times 309.92 K}{0.028 kg/mol}}$

= 524.5 m/s

Therefore, $v_{rms}$ speed for nitrogen is 524.5 m/s.

3 0

3 years ago

How many protons, neutrons, and electrons are contained in uranium-238?

monitta

It has 92 protons, 92 electrons, and 238 — 92 : 146 neutrons.

8 0

3 years ago

Which of the following statements is a true statement regarding a solution with [H1+] =1x10-5 M and [OH1-]= 1x10-9 M?

zheka24 [161]

Answer:

B. The [H1+] >[OH1-] and the solution is acidic

4 0

2 years ago