Leaving a beaker of water open to the air until it is empty is a phisscal or chemical change ?
Heating a piece of calcium carbonate is a physical or chemical change ?
Adding copper sulphate to crystal water is it a chemical or physical change?
How to seeds disperse and the reasom ?
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the degree of exactness of a mesurement is accuracy
Since this is not my area of expertise, I searched Google under the key words "physical chemical change" to get these possible sources:
http://www.chem4kids.com/files/matter_chemphys.html
http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson15.htm
http://www.quia.com/quiz/303980.html
(Broken Link Removed)
For your last question, you can use the key words, "seeds disperse." As a reason, imagine that you, your children, your grandchildren and so on lived in the same house. Generalize this to seeds.
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.
I hope this helps. Thanks for asking.
To determine whether leaving a beaker of water open to the air until it is empty is a physical or chemical change, you can analyze the process. In this case, the water in the beaker is exposed to the air, allowing for evaporation to occur. Evaporation is a physical change as it involves the transition of water from a liquid state to a gaseous state. Therefore, leaving the beaker of water open until it is empty is a physical change.
Heating a piece of calcium carbonate is a chemical change. Calcium carbonate undergoes a chemical reaction when subjected to heat, resulting in the formation of calcium oxide (quicklime) and carbon dioxide gas. This process is called thermal decomposition, where the compound breaks down into simpler substances. Hence, heating calcium carbonate is a chemical change.
Adding copper sulfate to crystal water is also a chemical change. When copper sulfate is dissolved in water, it forms a solution containing copper ions and sulfate ions. This dissolution process involves the breaking of ionic bonds between the copper and sulfate ions, resulting in a homogeneous mixture. Therefore, adding copper sulfate to crystal water is a chemical change.
Regarding the question of seed dispersal, different plants have evolved various mechanisms to disperse their seeds. Some common methods of seed dispersal include:
1. Wind dispersal: Seeds with lightweight structures or appendages, such as dandelion seeds or maple tree seeds (samaras), are dispersed by wind. The seeds have adaptations like feathery structures or wings that help them catch the wind and travel long distances away from the parent plant.
2. Animal dispersal: Certain plants have seeds that are dispersed through the consumption and subsequent excretion of animals. The seeds are often enclosed in edible fruits or berries which attract animals. After consuming the fruits, the animals excrete the seeds in different locations, aiding in their dispersal.
3. Water dispersal: Seeds that are buoyant or have specialized structures that allow them to float on water can be dispersed by streams, rivers, or ocean currents. These seeds can travel great distances and settle in new habitats.
4. Self-dispersal: Some plants have mechanisms to disperse their seeds themselves. For example, certain plants have fruits that dry out and split open, forcefully ejecting the seeds away from the parent plant.
The reason for seed dispersal is to ensure the survival and colonization of plant species in new areas. By dispersing their seeds, plants reduce competition for resources among their offspring and increase their chances of finding suitable conditions for growth and reproduction.