Dissolution

Question: Is Dissolving Sugar in Water a Chemical or Physical Change?

Is dissolving sugar in water an example of a chemical or physical change? This process is a little trickier to understand than most, but if you look at the definition of chemical and physical changes, you'll see how it works. Here's the answer and an explanation of the process.

Answer: Dissolving sugar in water is an example of a physical change. Here's why: A chemical change produces new chemical products. In order for sugar in water to be a chemical change, something new would need to result. A chemical reaction would have to occur. However, mixing sugar and water simply produces... sugar in water! The substances may change form, but not identity. That's a physical change.

One way to identify some physical changes (not all) is to ask whether the starting materials or reactants have the same chemical identity as the ending materials or products. If you evaporate the water from a sugar-water solution, you're left with sugar.

Whether Dissolving Is a Chemical or Physical Change

Any time you dissolve a covalent compound like sugar, you're looking at a physical change. The molecules get further apart in the solvent, but they don't change.

However, there's dispute about whether dissolving an ionic compound (like salt) is a chemical or physical change because a chemical reaction does occur, where the salt breaks into its component ions (sodium and chloride) in water. The ions display different properties from the original compound. That indicates a chemical change. On the other hand, if you evaporate the water, you're left with salt. That seems consistent with a physical change. There are valid arguments for both answers, so if you're ever asked about it on a test, be prepared to explain yourself.

http://chemistry.about.com/od/matter/f/Is-Dissolving-Sugar-In-Water-A-Chemical-Or-Physical-Change.htm

Chemical Reaction Quiz

2. Marco 

The student is able to distinguish between physical change and chemical reaction           1.Marco tears a piece of notebook paper into smaller pieces, tearing paper into pieces is an example of what kind of change?                2. Which process is an example of a physical change?           A. burning B. rusting .  C.flattening 3. Chemical changes result in new substances, but physical changes do not. Which process is an example of a chemical change? A. baking a cake B. chopping a tree  C. heating a cup of tea   4.  Which observation is a sign of a chemical change? A. A rotting potato gives off a bad smell. B. A melting block of ice leaves a large puddle. C. A cloud changes shape when blown by wind. D. A plaster statue breaks when it falls onto the floor.                      5. There are several differences between chemical and physical changes. Which process is an example of a chemical change? A. steam rising from a boiling pot of soup B. a metal railing rusting in damp weather C. alcohol evaporating from a cotton swab D. a piece of wood shrinking as it dries out Chemical reaction I researched more than requested and can accurately identify and explain a chemical reaction. I can identify and explain a chemical reaction. I still can’t identify and explain a chemical reaction. What I will do now.                                    .

Chemical vs Physical Change

Changes

Physical and Chemical Changes

Physical & chemical changes from butch2bn

Chemical and Physical Change

Xylem and Phloem

Vascular Systems of Plants

Xylem and phloem make up the big transportation system of vascular plants. As you get bigger, it is more difficult to transport nutrients, water, and sugars around your body. You have a circulatory system if you want to keep growing. As plants evolved to be larger, they also developed their own kind of circulatory systems. The main parts you will hear a lot about are called xylem and phloem.

It all starts with a top and a bottom. Logically, it makes sense. Trees and other vascular plants have a top and a bottom. The top has a trunk, branches, leaves, or needles. The bottom is a system of roots. Each needs the other to survive. The roots hold the plant steady and grab moisture and nutrients from the soil. The top is in the light, conducting photosynthesis and helping the plant reproduce. You have to connect the two parts. That's where xylem and phloem come in. 

                                                     Xylem  (UP)

The xylem of a plant is the system of tubes and transport cells that circulates water and dissolved minerals. As a plant, you have roots to help you absorb water. If your leaves need water and they are 100 feet above the ground, it is time to put the xylem into action! Xylem is made of vessels that are connected end to end for the maximum speed to move water around. They also have a secondary function of support. When someone cuts an old tree down, they reveal a set of rings. Those rings are the remains of old xylem tissue, one ring for every year the tree was alive. 

                                                   Phloem  (DOWN)

The fun never stops in the plant's circulatory system. Most plants have green leaves, where the photosynthesis happens. When those sugars are made, they need to be given to every cell in the plant for energy. Enter phloem. The phloem cells are laid out end-to-end throughout the entire plant, transporting the sugars and other molecules created by the plant. Phloem is always alive. Xylem tissue dies after one year and then develops anew (rings in the tree trunk). What is the best way to think about phloem? Think about sap coming out of a tree. That dripping sap usually comes from the phloem.

http://www.biology4kids.com/files/plants_xylemphloem.html