Formation Equations

realize that elements of the periodic table exists in different standard states or sometimes called natural states. When it comes to the natural world, we're going to say here at room temperature, which is approximately 25 degrees Celsius and standard pressure, which is approximately one atmosphere elements exist as either solids, liquids or gasses. So for a quick review on the periodic table, what we have here in red are the elements that exist as gasses. Now some of them are mono atomic in terms of the noble gasses from helium all the way down to radar. But other gasses exist in a di atomic form where there are two of them combined together. This includes hydrogen, which is H2, nitrogen, which is end to oxygen, which is 02 F two for flooring and cl two for chlorine, then we have a few elements that can exist in the liquid phase. This includes bombing, which is also die atomic and mercury, which is mono atomic. A vast majority of the other elements on the periodic table in their natural state or standard states exist in the solid form as mono atomic. And then here we have in the bottom row these that aren't solids, liquids or gasses. These have been formed within laboratory or because of their high atomic masses are very unstable. So they don't come along with a phase at standard room temperature or pressure. Now remember in terms of these three phases in a solid, the molecules are fairly tight packed together in a liquid. They're more free to move around one another and then gasses, they're greatly spread apart. So just keep in mind when we're talking about the natural standard state of elements, these this is how they exist in terms of phases and in terms of forms now we also have phosphorus, sulfur and selenium. These don't exist as mono atomic or die atomic atoms. Instead, they're going to exist as poly atomic molecules. Phosphorus exists as P four, sulfur is S eight and selenium and delirium, which are below. It exists as S. E eight and T eight. iodine also is di atomic, it exists as I too. So keep in mind these different forms of the elements in their standard or natural states.

here, it says which of the following elements is found in its standard state. If we take a look, we have I two. We know that I to iodine exists as a solid in its standard or natural state. 03 gas oxygen naturally exists as a die atomic molecule. It's 02 gas, not, 03 gas. 03 would be ozone. Next we have neon gas. Neon is a noble gas. Noble gasses. Most of them are gasses and their mono atomic. This would represent its standard state. And then here we have boron boron exist as a solid and it's mano atomic. It wouldn't exist as B to gas. So the only one in that standard ST would be option C.

in a formation equation, the standard state of elements combined together to form one mole of product here. In this example, it says right, the formation equation from methane style, which is ch three s h following the steps, it says step one right, the compound as a product. So ch three s h in a formation equation the coal, The product will always have a coefficient of one because, remember, we're making one mole of it step to write the standard states of the elements that make up the element as the reactors. So it's made up of carbon. Carbon is mono atomic, and the most common form of carbon is graphite plus Squam hydrogen hydrogen is diatonic and it's a gas plus sulfur. Sulfur is Polly Atomic. It's s eight, and it is a solid right. The formation equation with the appropriate coefficients for the reactant off formation equation is a rare instance where coefficient doesn't need a whole number. Sofrito balance this out. Remember, we make a list on both sides. So this is carbon, hydrogen and sulfur, carbon, hydrogen and sulfur. We have one carbon to hydrogen. Eight sull furs, one carbon, four hydrogen, one sulfur the cold fish into your has to be a one. We cannot change that. So we're gonna have to adjust the other coefficients. Your carbons air tied for both one and one. So that's fine. Here we have four hydrogen, but here we have to. So I'm gonna put a two here. That means the two gets distributed to give us four. Hydrogen is now. Then we have eight. Hydrogen is here, but only one here. I'm not allowed to put a coefficient in front of the product. So this is one of those rare occasions where I'm gonna have to do 1/ because 18 times eight will give me one. So now both sides of the equation have one sulfur involved. And then we can just say there's a cowfish. Ah, coefficient of one. If you want in front of the carbon graphite. So here, this would be our balanced equation. One mole of carbon graphite plus two moles of hydrogen gas react with 1/8 sulfur eight to produce one mole of methane style. So this would be our formation equation for methane tile.