Which is a chemical change?
A - splitting water into hydrogen and oxygen
B - breaking a block of solid ice into smaller pieces
C - freezing liquid water
D - boiling water
My answer: D
astle Bravo was the first in a series of high-yield thermonuclear weapon design tests conducted by the United States at Bikini Atoll, Marshall Islands, as part of Operation Castle. Detonated on March 1, 1954, the device was the most powerful nuclear device detonated by the United States and its first lithium deuteride fueled thermonuclear weapon.[1][2] Castle Bravo's yield was 15 megatons of TNT, 2.5 times the predicted 6.0 megatons, due to unforeseen additional reactions involving lithium-7,[3] which led to the unexpected radioactive contamination of areas to the east of Bikini Atoll. At the time, it was the most powerful artificial explosion in history.
Fallout, the heaviest of which was in the form of pulverized surface coral from the detonation, fell on residents of Rongelap and Utirik atolls, while the more particulate and gaseous fallout spread around the world. The inhabitants of the islands were not evacuated until three days later and suffered radiation sickness. Twenty-three crew members of the Japanese fishing vessel Daigo Fukuryū Maru ("Lucky Dragon No. 5") were also contaminated by the heavy fallout, experiencing acute radiation syndrome. The blast incited international reaction over atmospheric thermonuclear testing.[4]
The Bravo Crater is located at 11°41′50″N 165°16′19″E. The remains of the Castle Bravo causeway are at 11°42′6″N 165°17′7″E.
The correct answer is A - splitting water into hydrogen and oxygen.
To determine which of these options represents a chemical change, we need to understand the difference between chemical and physical changes.
A physical change occurs when the substance undergoes a change in its physical properties, such as size, shape, or state of matter, without any alteration in its chemical composition. Examples of physical changes include breaking a block of solid ice into smaller pieces (option B) or freezing liquid water (option C).
On the other hand, a chemical change involves a transformation in the chemical composition of the substance, resulting in the creation of new substances with different chemical properties. An example of a chemical change is splitting water into hydrogen and oxygen (option A).
Boiling water (option D) is a physical change because it involves changing the state of water from liquid to gas, without altering its chemical composition.
So, when considering the given options, the only one that represents a chemical change is option A - splitting water into hydrogen and oxygen.
A necessary condition for a chemical change is that the material final material is different from the original material.
For example, burning carbon in air gives carbon dioxide.
Material before change: carbon
product: carbon dioxide.
Since carbon is chemically different from carbon dioxide, burning carbon in air is a chemical change.
Based on the above, please give it another try.