10. When gases mix the total pressure is the sum of the partial pressures of the gases. This principle is known as: Dalton's Law Charles's Law Boyle's Law Graham's Law

## Step 1<br />The problem is asking us to identify the principle that states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each individual gas in the mixture. This principle is known as Dalton's Law of Partial Pressures.<br /><br />## Step 2<br />Let's briefly discuss the other laws mentioned in the options:<br />- Charles's Law states that the volume of a given mass of a gas is directly proportional to its temperature on an absolute scale if pressure and the amount of gas remain unchanged.<br />- Boyle's Law states that the pressure of a given amount of gas held at constant temperature is inversely proportional to the volume.<br />- Graham's Law states that the rate of diffusion of a gas is inversely proportional to the square root of its molar mass.<br /><br />## Step 3<br />From the above explanations, it is clear that only Dalton's Law is related to the total pressure of a gas mixture being the sum of the partial pressures of the gases.