How to Calculate Molar Mass

How to Calculate Molar Mass

Moles are a unit of measurement of chemicals. A mole is the atomic weight of a molecule of the chemical in grams and it is used very commonly in chemistry, so I’m going to show you how to calculate molar mass.

You can find the molar mass right on the periodic table. On the table, there is the element symbol, the atomic number, and the molar mass.

PeriodicTable-56a128ab5f9b58b7d0bc938c

Here I’ve got some elements:

 

Nitrogen’s molar mass is 14.0067 g/mol, for oxygen, it’s 15.9994 g/mol, and for silver, it’s 107.8682 g/mol.

The first method of finding the molar mass is to look right on the table (just like I did).

The second method is to add up the masses of each atom (.Add up the masses of the atoms that form the compound) I’ll show how with the chemical silver nitrate.


AgNO3

One Silver molecule: 107.8682 + one Nitrogen molecule 14.0067 + and three molecules of Oxygen: (15.9994 x 3)

107.8682 + 14.0067 + (15.9994 x 3) = 169.8731

AgNO3 = 169.87 g/mol


Let’s try another one:

NaOH

One Sodium molecule: 22.989769 + One Oxygen: 15.9994 + and one Hydrogen: 1.00794

22.989769 + 15.9994 + 1.00794 = 39.997 g/mol

NaOH = 39.997 g/mol


H2SO4

Two Hydrogens: (2 x 1.00794) + One Sulfur: 32.07 + Four Oxygens: (4 x 16.00)

(2 x 1.00794) + 32.07 + (4 x 15.9994) = 98.079 g/mol

H2SO4 = 98.079 g/mol


 

I hope you understand, leave a comment if you have any questions or if there are any mistakes ↓

 

Sources:

http://www.qrg.northwestern.edu/projects/vss/docs/propulsion/3-what-is-a-mol.html

https://www.youtube.com/watch?v=F9NkYSKJifs

Making Naphthalene Crystals

Making Naphthalene Crystals

I realized that time passes so fast, it was about a week since I made a new post. I feel like it has been for only 3 days. Anyways, let’s get started with the post.

I’ll try to make Naphthalene crystals. Naphthalene is a white crystalline solid with a characteristic odor. It’s melting point is about 80°C. If you leave it to expose air, it’ll change into a gas.

My Naphthalene:

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I put about 7 balls of Naphthalene into a 600 ml beaker, and I put a flask with cold water on top of it.

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The Naphthalene is vaporizing quickly. The vapors will get in contact with the cold water in the flask and turn back into a solid.

Crystals are also forming in the beaker, because it’s touching the cold air outside, just like what’s happening in the flask.

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All of the Naphthalene has changed into liquid, it was boiling a little too fast so I stopped the heat.

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The crystals are so fragile so I used a trash bag to make the crystals fall onto it.

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Here are the crystals. They look like fern leaves and snowflakes! But I wish the crystals were chunks, not thin like this. I looked in the internet for pictures of Naphthalene crystals, and they’re just like mine. The reason that it’s yellow is because the light is just reflecting it.

Here’s the beaker:

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I hoped you enjoyed the post, if you did, drop a like down below ↓

Does Mercury Conduct Electricity?

Does Mercury Conduct Electricity?

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I bought this from my science shop yesterday so that I could perform more experiments.

Why is it a liquid?

The reason for mercury being a liquid is complex. It is heavy; a chunk of iron can float on mercury. Compared to other metals, it does not conduct heat well. However, it conducts electricity fairly well.

Mercury is the only metal that is a liquid at normal temperatures and pressure. What makes mercury so special? Basically, it’s because mercury is bad at sharing… electrons, that is.

Most metal atoms readily share valence electrons with other atoms. The electrons in a mercury atom are bound more tightly than usual to the nucleus. In fact, the s electrons are moving so fast and close to the nucleus they exhibit relativistic effects, behaving as if they were more massive than slower-moving electrons.

Why does it conduct electricity?

Mercury is a liquid metal. As with all metals, the outer electrons are detached from the nuclei and form a kind of “sea of electrons” in which the rest of the atoms sit. A small electrical force, in other words a voltage, placed across any two points in this sea will make the electrons move, and that constitutes a current and makes a metal electrically conducting.

I wanted to see that mercury can conduct electricity. I opened mercury bottle, it has an inner closure, I’m not going to take it out because we need it.

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I’m going to put pins in it.

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I will flip the bottle and the mercury will be in contact with the pins and the circuit will turn on.

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It works nicely!

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This chemical will go into my favorite chemical list!

https://www.quora.com/Why-does-mercury-conduct-electricity-so-well

https://www.thoughtco.com/why-is-mercury-a-liquid-608454

The Silver Tree

The Silver Tree

download

As said on my post (it finally came 2) the silver nitrate is only 10 grams and it’s about $20. 10 grams is a little amount and it is very expensive, so I hope I don’t make any mistakes. The classic silver tree demonstration! Very simple to set up and perform, it’s great to introduce kids to the world of chemistry.

Things you’ll need: copper wire, silver nitrate, a beaker, and distilled water.

  1. Pour 120 ml of distilled water into the beaker.20170624_111346
  2. Pour about 4 grams of silver nitrate into the beaker.20170624_112031
  3. Make a copper coil by wrapping copper wire around something round and taking it out. Put the copper coil into the beaker.20170625_102905

As you could see the reaction has started.

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0 minutes

The more silver nitrate you add, the quicker the reaction starts.

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15 minutes

 

Silver Crystals are covering the copper. It looks very pretty.

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30 minutes

 

Prettiest experiment I ever performed.

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50 minutes

This experiment is very easy to setup and very fun for kids.

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1 hour

You can keep going, but the more you wait, the more crystals will grow and turn blacker because when silver nitrate absorbs light, it will turn black. Now the silver nitrate is turning into silver metal.

Now I’m going to filter the silver metal out and see what comes out.20170625_115600

I got the silver metal. I put it in a bottle to preserve it.

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The silver nitrate is in solution and the metallic copper will dissolve to form copper nitrate; as it does so, the silver in solution will be precipitated out as metallic silver. That is, the silver in solution is exchanged for copper and the copper that is not in solution is substituted for silver. Hope this makes sense!

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