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>
Mutualism is the ecological interaction between two organisms.
1. When a big fish eats a tinier fish
2. When a plant absorbs water
Answer:
Potassium Dichromate is an orange to red colored, crystalline, inorganic compound that emits toxic chromium fumes upon heating. Potassium dichromate is highly corrosive and is a strong oxidizing agent. This substance is used in wood preservatives, in the manufacture of pigments and in photomechanical processes, but is mainly replaced by sodium dichromate. Potassium dichromate primarily affects the respiratory tract causing ulcerations, shortness of breath, bronchitis, pneumonia and asthma but can also affect the gastrointestinal tract, liver, kidneys and immune system. This substance is a known human carcinogen and is associated with an increased risk of developing lung cancer and cancer of the sinonasal cavity. (NCI05)
0.2M means 0.2mol CaCl2/1L solution.
This question didn't give us a density of the solution so needs an assumption that the solution has equal volume to water.
xmol/0.5L=0.2M
x = 0.1
0.1mol of CaCl2 is needed. Ca=40g/mol, Cl=35.5g/mol.
CaCl2 0.1mol = (40+35.5*2)*0.1=11.1g
