How long will you live? 10,000 years ago, the average human life lasted just over 30 years, and then a hundred years ago that number was up to 50. If you were born in the last few decades in the developed world, then your life expectancy is 80 years. But that is of course assuming that no major breakthroughs happen during your lifetime that can slow the process of aging.
That may be a very bad assumption.
According to Dr. Fiona Ginty, aging is not always recognized as a disease. There are plenty of diseases we do acknowledge like diabetes, heart disease, and Alzheimer’s. At their core, aging may be responsible for all of them.
And yet aging seems natural because it’s something that we do from birth and for a while it makes us better. Bigger, stronger, faster, more intelligent. But then at some point in your life it reverses and aging makes our bodies decay and degrade.
Why do we have to age?
Scientists are now realizing there is a fundamental cellular mechanism at the heart of aging. Do we age at the macroscopic level because our cells are aging at the microscopic level? To a great extent, yes. There’s only a finite number of times a cell will divide.
The key discovery was made by a biologist named Hayflick. He was studying normal human cells. He found that they can only divide a finite number of times, usually about 50. Beyond that, the cell becomes senescent, which means it’s an aged cell. It can divide no longer. It lives for a little while but it’s the accumulation of these senescent cells in our bodies that leads to aging on the macroscopic scale.
So it’s as though cells have this little timer inside them that tells them when to stop dividing. But how do they know, and what is that timer?
According to Dr. Ginty, “telomeres are like how your shoelaces have a little bit of plastic at the end to stop them from fraying.” So when your telomeres wear out, the chromosomes stop multiplying. When they work, they keep the chromosome together and stop them from sticking to other chromosomes. Dr. Ginty explains that every time a cell divides, it loses about 200 base pairs of telomere due to the mechanics of the action. “There’s only so much space when DNA polymerase does its job of replicating when it’s copying.”
So the telomere getting shorter is like your molecular clock. The cellular clock inside each cell that tells it how many times it has divided. Would you want to have your telomeres measured?
Well, we can at least lengthen our telomeres!
There have been associations made with lifestyle and exercise showing that longer telomeres are associated with a more active lifestyle.
If we could stop the telomeres from shortening, maybe the cells would live forever. There’s another enzyme involved called telomerase, and it keeps rebuilding.
Telomase rebuilds the telomere, and there is one animal that doesn’t seem to age—the lobster. It just gets bigger over time. It doesn’t get weaker and its chromosomes don’t change. It has long telomeres that do not shorten, so it only dies when it gets eaten by something else like a human. So how can we be more like a lobster?
Well, that answer is a little complicated.
Unfortunately, cancer is a perfect example of telomerase being hyperactive. In the end, it becomes an unregulated growth situation. —This is the double-edged sword of telomeres and telomerase. Cancer cells have really long telomeres, and they can divide indefinitely, and that is the problem with cancer. Cancer is dividing cells that won’t stop and they won’t die. So, in a way, cancer is the immortal cell living within us.
So maybe we have telomeres that shorten for a very good reason; otherwise they could become cancerous. One of the theories there is that the cells divide that limited number of times because it stops them from accumulating damage that may be detrimental. Telomeres might stop cells from becoming cancerous.
Over the past hundred years, developments in medicine have increased human lifespan more than we could have imagined, and I can only expect that the next hundred years will bring similarly incredible results. I’m not sure where or how they will take place, but you can bet that your life expectancy today will not be the actual age at which you die.
Mary had a shorn a little lamb Its fleece was filthy grey. Mary had to scrub it clean. For a sock on Mom’s birthday.
She took it to an automat. But wondered what to add. Sodium carbonate will do the trick. But adding too much was bad.
So, Mary had to figure out How many atomic grams to use. To do this she drew up its molar mass And started to deeply muse.
Let us learn here to find molar mass, specially with an example molar mass of Na2Co3. Molar mass is defined as its “gram-formula-mass.” In other words, molar mass is how much one mole of the substance weighs in terms of “atomic mass.” A mole is a number: 6.02×1023. Just like a dozen is 12, one mole is 602000000000000000000000. Scientists use moles as a base number so they can compare groups of atoms. Just as you can compare one carbon atom to one helium atom, you can compare one mole of carbon to one mole of helium.
*to abbreviate “mole,” just shorten it to “mol.”
The larger the atom is, the heavier it weighs. This makes sense, right? Well, the periodic table is organized from smallest to largest, in which the number of protons and neutrons largely determine the weight (Atoms have electrons, but they are so small they weigh “nothing”).
For example, in the top left corner, Hydrogen has one proton, one electron, and no neutrons. So it’s atomic number is One (for one proton) and its atomic weight is One (for one proton and one neutron)
One mole of hydrogen atoms will be its atomic weight. One mole of hydrogen atoms weighs One gram/mol.
The next one is helium, which has two protons and two neutrons. This means the atomic number is Two (for two protons) but the atomic weight of the atom is FOUR (two protons and two neutrons).
One mole of helium atoms weighs Four gram/mol.
**Here’s a quick tip, in the more common elements near the top of the chart, an atom’s protons and neutrons are “ideally” the same. So, the atomic weight is simply doubled the atomic number. Pretty easy, huh?
Na2Co3 is made up of two sodium atoms, one carbon atom, and three oxygen atoms. We know the number of each atom because the number of atoms per element is listed right after the symbol.
Let’s look at each atom:
Then, just add up the atomic weights of each:
(2 x 22.990) + (12.011) + (3 x 15.999) =
44.980 + 12.011 + 47.997 =
Looks like Little Mary has her work cut out for her! Keep in touch of expert tutors for a homework help.
Chemical reactions are the stuff of life. When we cook food, start a motor, or washing our hands in soap, we depend on chemical reactions. There are many types of reactions, but all of them have one thing in common. They have to be balanced.
What does “balance” mean?
It means that the charges on both sides of the equation must cancel out to be neutral.
An atom is made up of protons, neutrons, and electrons.
The nucleus, which is made up of protons and neutrons, has a positive charge, due to the protons. The number of orbiting electrons balances the number of protons so that an atom ideally is neither positive nor negative.
But if an atom LOSES an electron, that means the atom becomes positively charged. Look at the picture above. See how it has FOUR protons, FOUR neutrons, and THREE electrons? This breaks down to FOUR positive charges, FOUR neutrals, and THREE negatives. They cancel each other out, leaving ONE positive charge left. So this atom has a charge of +1.
If this atom GAINS an electron, it will have FOUR electrons to match the FOUR protons. Its charge will be ZERO.
If this atom GAINS TWO electrons, it will have FIVE electrons to the FOUR protons. Its charge will be -1.
An atom that gains or loses an electron is called an ION. An atom that LOSES an electron for a positive charge is called an CATION (pronounced cat-ion). An atom that GAINS an electron for a negative charge is called an ANION (pronounced an-ion).
With me so far? Okay, now let’s look at the periodic table.
See how it’s color coded? The table is divided into metals and nonmetals (and metalloids, which mean they can be both, but we won’t worry about those).
Metals are purple and to the left (except for Hydrogen at the top). Metals tend to LOSE electrons to create positive charges.
The periodic table gives you a hint: the atoms at the extreme left lose ONE electron for a +1 charge. Li, Na, K, Rb, Cs, and Fr all lose ONE electron in a reaction. Their ions have a +1 charge.
The next column to the left tend to lose TWO electrons in a chemical reaction, for a +2 charge. Be, Mg, Ca, Sr, Ba, and Ra ions all have +2 charges.
We’ll leave the shorter stacks out for now. Those ions’ charges vary.
On the right side are the non-metals. These are gases like helium and nitrogen, liquids like chlorine and iodine, and substances like sulfur. The non-metals are tricky.
That is because many of these elements exist in molecules consisting of 2 atoms. Oxygen gas exists as O2. Nitrogen gas exists as N2. Liquid chlorine is Cl2.
Tip: We do not have to worry about the extreme right. They are ALWAYS balanced. He, Ne, Ar, Kr, Xe, and Rn generally do not react with anything. They are also found in molecules of 2: He2, Xe2, etc. These are called “noble gases” because they do not react.
In a chemical reaction, many of these molecules break up into individual anions. These anions have a negative charge. The column to the left of the noble gases GAINS ONE electron. F, Cl, Br, and I anions have a -1 charge. The next column gains TWO electrons: O, S, and Se anions have a -2 charge. In the next column, Nitrogen (N) has a -3 charge.
There are 2 exceptions. Carbon (C) can either gain or lose electrons. Way over on the left hand side, Hydrogen (H) ALWAYS loses its electrons for a +1 charge. That is why it is placed with Li and other positive ions.
So, let’s recap all this:
Metals: always LOSE electrons for ions with positive charges.
Non-metals: mostly GAIN electrons for anions with negative charges. Many non-metals have a pure state of TWO atoms joined together: H2, F2, S2, etc.
Take a breather—this is where the fun begins!
Let’s put it together with some basic chemical reactions.
Balancing Chemical Equations Example #1
Common table salt has a chemical label of NaCl. That means it has one Sodium (Na+1) cation and one Chlorine (Cl-1) anion.
How do we make salt? We just join the two atoms. Na is in the far left column, which means it LOSES ONE electron. Cl is in the non-metal column that GAINS one electron. So the two are a perfect fit. This is why salt is so common and cheap!
Now to make it more complicated.
Remember how Cl only exists in a pure state as two atoms joined together? Cl2. What happens to the other Cl atom? It needs to gain an electron. The easiest solution is to add another Na+1cation for it to hook up with. So, our formula now reads:
2Na+1 + Cl2 -> 2NaCl
Note the placement of the 2. NaCl is a balanced formula, so we can’t change it to read anything else (NaCl2 would imply that one molecule of salt has two chlorine atoms for one sodium atom and this is not correct. The ratio is 1:1.Na2Cl2 is also incorrect because one molecule has two Na and two Cl, while in reality each molecule only has one). But we have to account for every atom and for every charge. The Na atoms have a +1 charge each. When we break up Cl2, each Cl anion has -1 charge each. Placed together, these positive and negative charges cancel each other out and each atom is accounted for.
**(There are some other things we can add to the equation, such as the presence of heat that is released during the reaction, and that these reactions take place in solutions, but that’s getting ahead of the game).
Balancing Chemical Equations Example #2
Think you got it? Let’s try something else: Magnesium Bromide.
Magnesium cation is in the second to left column, so it has a +2 charge.
Bromine is in the second to right column, so it has a -1 charge.
Technically, you can write:
Mg+2 + 2Br-1 -> MgBr2.
Even though we need 2 Br atoms to cancel the +2 positive charge on Mg, we have to remember that Bromine does not exist as individual atoms in a natural state. Like Chlorine, Bromine’s natural state is two atoms joined together as Br2.
So the right answer is:
Mg+2 + Br2 -> MgBr2.
Balancing Chemical Equations Example #3
How about water? We all know this one: H2O!
O gains 2 electrons while each H loses one electron. We know we need two Hydrogen atoms for each Oxygen atom.
H2 + O -> H2O
Well, not quite.
Hydrogen loses atoms, so it has a positive charge. It also exists as an H2 molecule in its natural state, so we’re okay there.
But Oxygen also exists as O2in its natural state. We need to account for the extra O!
Let’s put it together:
H2 + O2 -> H2O
Almost there! We need another O on the right to balance the number of Os on the left. We can’t write the final equation as H2O2 because one molecule of water only has one oxygen atom and we would be stuck with an extra -2 charge because of the second O. (It would look like H2O2-2 YIKES!). We can simply add an extra water molecule altogether:
H2 + O2 -> 2H2O
Now we have TWO Oxygen atoms on each side. But now we have FOUR Hydrogens on the right (TWO molecules of water, each with TWO hydrogens). How can we balance the FOUR on the right and TWO on the left?
Add another Hydrogen molecule:
2H2 + O2 -> 2H2O
Now everything matches up: Four Hydrogen and Two Oxygen atoms on each side. This is balanced!
Balancing Chemical Equations Example #4
Want something really horrible to try?!?
Let’s start with a balanced formula: HSO3
Let’s break this down. Hold on to your hat!
We know H has a +1 charge. That means SO3has a -1 charge altogether.
We’ll keep SO3 intact for this equation. It’s pretty hard to break up this molecule (for reasons that are too complex to get into for now. ).
So, what is HSO3 good for, anyway, you ask? It helps soften your water!
Hard water is the presence of Calcium (Ca), or Calcium chloride (CaCl2) which is left behind when water dries. It clogs your drains and leaves deposits on your pans. You need to get rid of Ca and Cl in a filtration system.
This will be in two steps.
●Drop a resin ball containing HSO3 in your tank. (We’ll ignore the presence of water in the equation). Let’s see what happens. The resin ball will extract calcium from water by swapping it out with the Hydrogen from the SO3.
Ca+2 + HSO3 -> ???
SO3 has a -1 charge, while Ca has a +2 charge. So, we need two SO3 for each Ca. ->Ca(So3)2
The Ca swaps out for the H atom, freeing it in the water.
Ca+2 + HSO3 -> Ca(So3)2 + 2H+
Balance out the number of S, O, and H atoms on the left
Ca+2 + 2HSO3 -> Ca(So3)2 + H2(remember hydrogen in its natural state)
We have 1 Ca, 2 H, 2 S, and 6 O atoms on each side!
That takes care of the calcium!
●Now, what about the chlorine in CaCl2? We need to get rid of that element as well.
Let’s drop another resin ball in our pool of water, made up of NaOH. Na has a +1 charge, while OH has a -1 charge (remember that O has a -2 charge while H has a +1 charge).
NaOH+ Cl– -> NaCl + OH–
NaCl should look familiar—it’s table salt, from our first example!
Final step is pretty easy. The excess H+ atoms swapped out from the first resin ball and the OH- molecules from the second resin ball will join together and form water in your pool! H+ + OH–-> H2O.
OR, more correctly:
H2 + (OH–)2 -> 2H2O
Our final reaction, putting both resin balls in the same pool:
CaCl2 + HSO3 + NaOH->Ca(SO3)2 + NaCl + H2O
Now balance out the number of atoms on each side:
CaCl2 + 2HSO3 + 2NaOH -> Ca(SO3)2 + 2NaCl + 2H2O
Compare the numbers to make sure:
1 Ca; 2 Cl, 2 S; 2 Na; 8 O; 4 H -> 1 Ca, 2 S; 2 Na; 2 Cl; 4H; 8 O
Congrats, all the salt from the water are extracted and are stored in the resin balls. In exchange, we created more pure water released into your pool!Bravo!