Can someone please help me with this....?

ankoles [38]

Answer:

C, physical change

Explanation:

take a look at the equation. Next to each form of water do you see the little (g) and (l)? These represent the state of matter the water is in. So, the water is going from a gas to a liquid. The chemical compound is the same so its a physical change, not chemical, and it is reversible. You could change the liquid water back to the gas through evaporation. Endothermic has literally nothing to do with this equation so you can easily eliminate that answer choice.

7 0

3 years ago

How many protons are in nitrogen-15?

valentina_108 [34]

7 protons. As well as in nitrogen-14. The difference between nitrogen-14 and nitrogen-15 is in a number of neutrons. In nitrogen-14 - 7 neutrons, in nitrogen-15 - 8 neutrons.

4 0

3 years ago

What is the concentration of the solution prepared by dissolving 2.35 g of KBr (M = 119 g/mol) in 250 mL of water?

dusya [7]

Answer:

The concentration of KBr is $C = 0.07899 \ mol L^{-1}$

Explanation:

From the question we are told that

The mass of KBr is $m_{KBr} = 2.35 \ g$

The molar mass of KBr is $M_{KBr} = 119 g/mol$

Volume of water is $V = 250 \ mL = 250 *10^{-3} = 0.250 \ L$

This implies that the volume of the solution is $V = 250 mL$

The number of moles of KBr is

$n = \frac{m_{KBr}}{M_{KBr}}$

Substituting values

$n = \frac{2.35}{119}$

$n = 0.01975 \ mol$

The concentration of KBr is mathematically represented as

$C = \frac{0.01975}{0.250}$

$C = 0.07899 \ mol L^{-1}$

3 0

3 years ago

Iodine-131 is one of the most important isotopes used in the diagnosis of thyroid cancer. One atom has a mass of 130.906114 amu.

emmainna [20.7K]

Iodine-131 is one of the most important isotopes used in the diagnosis of thyroid cancer. One atom has a mass of <u>130.906114</u> amu.\

<h3>What is thyroid cancer?</h3>

Cancer that originates in the tissues of the thyroid gland is known as thyroid cancer. It is a condition where cells develop improperly and are susceptible to spreading to different bodily regions. A bump in the neck or swelling are examples of symptoms. Thyroid cancer is not always diagnosed because it can move from other parts of the body to the thyroid.

Young age radiation exposure, having an enlarged thyroid, and family history are risk factors. Papillary thyroid cancer, follicular thyroid cancer, medullary thyroid cancer, and anaplastic thyroid cancer are the four primary kinds. Ultrasound and tiny needle aspiration are frequently used in diagnosis. As of right now, it is not advised to screen those who are healthy and at normal risk for the disease.

To learn more about thyroid cancer from the given link:

brainly.com/question/11880360

#SPJ4

5 0

2 years ago

TUESDAY:

Rzqust [24]

Protons are positive
Neutrons are neutral
Electrons are negatively charged

5 0

3 years ago

Read 2 more answers