Give one example of a physical change and one example chemical change to prove the law of conservation of mass
Answers
Answer:
Example 1: The Bonfire/Campfire
One common example you’ll come across is the image of a bonfire or campfire.
Picture this: you’ve gathered some sticks with friends and lit them with a match. After a couple of toasted marshmallows and campfire songs, you realize that the bonfire, or campfire, you've built has completely burned down. All you’re left with is a small pile of ashes and some smoke.
Your initial instinct might be to assume that some of the campfire's original mass from the sticks has somehow vanished. But it actually hasn’t—it’s simply transformed!
In this scenario, as the sticks burned, they combined with oxygen in the air to turn into not just ash but also carbon dioxide and water vapor. As a result, If we measured the total mass of the wooden sticks and the oxygen before setting the sticks on fire, we'd discover that this mass is equal to the mass of the ashes, carbon dioxide, and water vapor combined.
Example 2: The Burning Candle
A similar law of conservation of mass example is the image of a burning candle.
For this example, picture a regular candle, with wax and a wick. Once the candle completely burns down, though, you can see that there is definitely far less wax than there was before you lit it. This means that some of the wax (not all of it, as you’ve likely noticed with candles you’ve lit in real life!) has been transformed into gases—namely, water vapor and carbon dioxide.
As the previous example with the bonfire has shown, no matter (and therefore no mass) is lost through the process of burning.