The relationship of radiation with distance obeys the inverse square law. Therefore, doubling the distance decrease the radiation by a factor of 4. The new count is 250.
1) Applying the same principle, the count decreases by a factor of 100. The new count is 10
2) An alpha particle is 4He2 and the Hydrogen can be represented as 1H1
14N7 + 4He2 - 1H1
= 17X8
Proton number 8 belongs to Oxygen. Therefore, the resultant nucleus is:
17O8
3) 185Au79 - 4He2
= 181Ir77
4) X - 4He2 = 234Th90
X = 238U92
5) Beta emission results in the same nucleon number but an increase in the proton number; therefore, the result is:
234Pa91
Only one. variable to get a reliable results you only have to change one.
Answer:
Try this link https://chem.libretexts.org/Courses/Mount_Aloysius_College/CHEM_100%3A_General_Chemistry_(O'Connor)/08%3A_Solids_Liquids_and_Gases/8.E%3A_Solids_Liquids_and_Gases_(Exercises)
Answer:
The correct answer is the option c)He thought the mold had released a chemical that prevented the bacteria’s growth.
Explanation:
In the 1920s, Alexander Fleming was working in his laboratory at St. Mary's Hospital in London when, almost by accident, he discovered a naturally growing substance that could attack certain bacteria. In one of his experiments, Fleming observed that colonies of a bacterium had been depleted or removed by a mold that grew on the same Petri dish. He observed that the bacteria furthest from the fungus had grown to produce large-sized colonies, while the colonies closest to the fungus were tiny. He determined that mold made a substance that could dissolve bacteria. The fungus was penicilium chrysogenum and thus Fleming called this substance penicillin, by the name of the mold that produces it. Thus, after several years of experiments in 1930, Howard Florey and Ernest Chain developed at Oxford University the procedures to produce pure penicillin from the fungus that Fleming isolated. Thus penicillin could be concentrated by Florey and Chain, and in 1945 they shared with Fleming the Nobel Prize in Medicine.
Then, <u><em>the correct answer is the option c)He thought the mold had released a chemical that prevented the bacteria’s growth.</em></u>
Chemical Property
<u>Explanation:</u>
When a substance is changed into another substance, may be due to addition of some other substance or removal of water from that substance.
* its identity changes
*its reactivity changes
*reactivity towards water, air and many other substances will change
*its chemical composition changes
and all these changes occurs due to the chemical properties.
If the physical property changes then there will be change in the state of matter, but its boiling point, melting point , reactivity towards water, air and other substances will not change, and it will not lose its identity.
