Question 1: Is the evaporation of salt water into salt and water a decomposition reaction? No. The evaporation of brine into salt and water is a physical change, while the decomposition reaction is a chemical change.
Question 2: Heating salt water causes the water to evaporate, leaving the salt behind. Is it a physical change or a chemical change? 1. If boiling water heats liquid water and turns. in water vapor, the temperature of the steam is 100 degrees, equal to the original temperature of water
2. If ordinary water evaporates into carbonated water, the steam of water evaporates and absorbs heat if there is no external heat. source, the temperature of the water vapor is lower than the temperature of the original liquid water.
3. To be clear, the temperature of sparkling water is not necessarily higher than 100 degrees Celsius, but it can be said to exist from absolute 0 degrees (-273 ofdegrees Celsius) at more than 1000 degrees, so liquid water becomes gaseous Water depends on its process. Because it is endothermic in the first place, if there is a heat source to provide it, the temperature can actually remain unchanged; if there is no heat source to provide energy, the temperature will inevitably drop!
Question 3: Add salt to salt water, () does not change, evaporate water in salt water, () does not change, quality of water does not change change
The mass of salt remains unchanged
Put ten grams of salt in ninety grams of water and salt makes up 10% of salt water.
We need to clarify the requirements of the question: Calculate the percentage of salt water that is salt after adding 10 grams of salt to 90 grams of water.
We know that brine is made up of water and salt. In this problem we have 90 grams of water and 10 grams of salt.
In order to calculate the percentage of salt in the brine, we must first calculate the total weight of the brine. The total weight of the brine is equal to the weight of the salt plus the weight of the water, or 10 grams + 90 grams = 100 grams.
Next we need to calculate the proportion of salt in the brine. This ratio can be found by dividing the weight of salt by the total weight of brine. The proportion of salt = 10g/100g = 0.1 or 10%.
So, salt makes up ten percent of the brine.
The method of formation of salt water is as follows:
1. Sun Salt: Pour sea water into a shallow container and place it in a sunny location. Allow the heat of the sun to evaporate the water, ultimately leaving salt crystals behind.
2. Boiling evaporation: pour sea water into a saucepan, heat over medium heat, wait until the water is about to evaporate, then put on low heat and evaporateSlowly pour in the water until you have pure salt crystals.
3. Filter water to make salt: Put sea water in a container, filter it with filter paper or filter sieve, separate the water and finally get salt crystals.
4. Drop crystallization method: pour sea water into a container, use a thin tube to drop water on the surface of the newly evaporated water, and drop water repeatedly to observe the formation gradual formation of salt crystals.
5. Frozen salt extraction method: Put the sea water in a freezer and freeze it. As the water cools, salt crystals will form. Salt crystals are made by gradually forming ice cubes and then melting the ice cubes with hot water.
6. Electrolysis method: pour sea water into a container, use an electrolysis device, and apply electricity todecompose the seawater, and the salt will precipitate.
7. Artificially Added Salt: Add an appropriate amount of salt to drinking water to make brine. This method is often used in medical or sporting situations to replenish the salt the body needs.
8. Food Processing: During food processing, salt water is sometimes used as a preservative or seasoning. For example, brine is commonly used as a preservative in meat processing, while fermented foods like kimchi use brine as a seasoning.
9. Artificial crystallization: In laboratories or industrial production, chemical methods can be used to artificially synthesize salt crystals. For example, sodium ions and chloride ions are bonded together through a chemical reaction to form sodium chloride crystals.