What is the difference between “amount” and “concentration”?

It is vital in chemistry to understand the difference between amount of a sample and the concentration of a sample. An amount is a quantity of something; a concentration is an amount of something in a volume of something else. So 10 grams of sugar is an amount, while 10 grams of sugar dissolved in 100 milliliters of water is concentration. Amounts in chemistry are usually expressed as moles; whereas concentrations use the term molar. A mole of something is the molecular weight for the compound expressed as grams. So if the molecular weight of a compound is 245, then one mole of that com- pound would be 245 grams. A one molar solution would be 245 grams dissolved in one liter of solvent (water).