Final answer:
Combining different substances can cause a change in the total weight of matter. Depending on the reaction, the weight can either increase or decrease.
Step-by-step explanation:
Combining different substances can affect the total weight of matter. When two or more substances are mixed, a chemical reaction may occur, resulting in the formation of new substances. These new substances may have different weights compared to the original substances, leading to a change in the total weight of matter.
For example, when baking soda (sodium bicarbonate) is combined with vinegar (acetic acid), a chemical reaction takes place, resulting in the formation of carbon dioxide gas, water, and a salt called sodium acetate. The weight of the carbon dioxide gas that escapes into the air can make the total weight of matter decrease.
On the other hand, some reactions may result in a new substance that is heavier than the original substances. For instance, when iron is exposed to oxygen in the presence of moisture, it undergoes a chemical reaction called rusting. The resulting iron oxide (rust) is heavier than the original iron, thus increasing the total weight of matter.
Learn more about how combining different substances affects the total weight of matter