Physical, or mechanical, weathering happens when rock is broken through the force of another substance on the rock such as ice, running water, wind, rapid heating/cooling, or plant growth. Chemical weathering occurs when reactions between rock and another substance dissolve the rock, causing parts of it to fall away.

During metamorphism, a rock may change chemically. Ions move in or out of a mineral. This creates a different mineral. The new minerals that form during metamorphism are more stable in the new environment.

Metamorphism is the addition of heat and/or pressure to existing rocks, which causes them to change physically and/or chemically so that they become a new rock. Extreme pressure may also lead to foliation, the flat layers that form in rocks as the rocks are squeezed by pressure.

Although metamorphic rocks typically form deep in the planet’s crust, they are often exposed on the surface of the Earth. This happens due to geologic uplift and the erosion of the rock and soil above them. At the surface, metamorphic rocks will be exposed to weathering processes and may break down into sediment.

Metamorphism is a process of mineral assemblage and texture variation that results from the physical-chemical changes of solid rocks, caused by factors such as crust movement, magma activity, or thermal fluid change in the earth.

When copper reacts with the elements (oxygen, water and carbon dioxide), it turns from its element color of reddish-brown to green. This chemical reaction is hydrated copper carbonate, and a famous example of it is the Statue of Liberty.

There are five signs of a chemical change:

• Color Change.
• Production of an odor.
• Change of Temperature.
• Evolution of a gas (formation of bubbles)
• Precipitate (formation of a solid)

When eggs are fried, they absorb heat energy. This breaks the weak chemical bonds that maintain the shape of the egg white proteins, causing them to uncurl. Therefore, frying an egg is a chemical change because it results in the formation of new particles.

Frying an egg involves a chemical change. The heat in the frying process gives energy to the egg’s molecules and brings about a permanent change in the substance. Chemical changes result in the formation of new substances, and the changes that occur cannot be reversed (at least without other chemical changes).

Cooking an egg is a set of chemical changes because chemical bonds are broken and new ones are made, resulting in the formation of new substances. In this case many of the bonds broken are those which cause the egg’s proteins to be folded into a globular shape.

You know it’s true. Toast is a thousand times better than bread, and that is just a fact. It’s a chemical reaction between the amino acids and sugar in bread when it’s cooked, a form of non-enzymatic browning.

Toasting bread is a chemical change. Adding heat to the bread cooks it, changing it on a molecular level. A chemical change can’t usually be reversed,…

When you sharpen your pencil, you have only caused a physical change. The sharpener has cut off some of the wood and maybe also some of the graphite, but the atoms of the wood and graphite have not changed chemically.

When we put food into our mouths and chew it, it is broken down into smaller pieces for easier digestion by the stomach. This is a physical change.

The chemical change in a rotting banana is the chemicals breaking down the flesh of the banana. The chemicals come from the air and get in the banana.

Batteries use a chemical reaction to do work on charge and produce a voltage between their output terminals. The basic element is called an electrochemical cell and makes use of an oxidation/reduction reaction. An electrochemical cell which produces an external current is called a voltaic cell.

Enzymes and digestive juices in the stomach work to chemically break down proteins into amino acids. This is a chemical change.

Your stomach contains hydrochloric acid, and too much of this causes indigestion. Antacid tablets contain bases such as magnesium hydroxide and magnesium carbonate to neutralise the extra acid.

Food is chemically changed in digestion when new, smaller substances are formed. These chemical changes are examples of chemical digestion. Chemical digestion begins in the mouth when enzymes in saliva begin to break down carbohydrates. Most chemical changes in digestion occur in the small intestine.

Decomposition reaction takes place during digestion of food since it involves breaking down the large nutrient molecules in food into smaller molecules.

what type of chemical reaction takes place when ammonia and hydrogen chloride gases are mixed? NH3 + HCl → NH4Cl.. ammonia and hydrochloric acid reacts to form single product ammonium chloride. NH3 is a base and HCl is an acid and they react together it is therefore also an neutralisation reaction.

Reaction of Zinc with Dilute Sulphuric Acid Zinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas is evolved. This is a single displacement reaction of a non-metal by a metal.

When dilute sulphuric acid is poured on zinc granules, then zinc being more reactive than hydrogen displaces it from the acid and forms zinc sulphate and hydrogen gas.