I have looked up multiple definitions and they still seem the same to me. Can anyone help a non-science person wrap my head around the concept?
In: Chemistry
Best way I can explain it is density is how much of one or more molecules is packed into a certain space – the more tightly its packed, the more dense it is. It’s about mass (weight) and volume (how much space is taken up). Concentration is a ratio. It’s when you want to know how much of molecule A is in mixture B or how many molecules are there per a certain amount. Density is consistent. Molecule A will always have the same density (Density changes when you mix stuff). But concentration can be changed. Like adding salt to water. The more salt, the higher the concentration of salt in the water. The ratio of salt to the combination of salt and water gets bigger. I hope I explained that well, not sure if it was 5 yo level, but I hope it at least helps you a bit.
Density measures the amount of mass per unit of volume in a substance. Concentration describes the amount of a substance dissolved in another substance. Changing the concentration of a solution changes the density of the solution.
Let’s break that down, take 1l of liquid with salt in it, say the density is 1.1 kg/litre. You have no information as to how much salt, only about the 2 combined.
If I said the concentration was 100g/litre now you know how much salt there is in the volume.
There is a relationship between the 2, increasing the concentration (eg adding more salt) will raise the density, as the combined salty liquid is heavier/kg
There isn’t a difference. We use the word ‘concentration’ when there are other substances around. I.e. if a block of salt was standing in a vacuum we would talk about its density, and if we dissolve salt in water we would talk about its (now much lower) concentration. The essence of the number (amount / volume) is identical.
Density is a broader term. Concentration is for solutes dissolved in solvents. Also, density is typically represented as mass per volume, whereas concentration is in molar units (per particle) per volume. The two can be interconverted by a factor of average molecular weight.
So basically:
density = how dense something is
concentration = how dense something is, when its dissolved in something else.
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