<u>Answer:
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When the outer electron shell is full in an element, this creates a Noble gas.
<u>Explanation</u>:
Noble gases are the elements that belong to group 18 in the periodic table. Noble gases are also called as inert gases. The outermost shell of the noble gases are fully filled by electrons. Due to this the noble gases don’t react with any other elements and remain isolated.
There are 6 noble gases in the periodic table. They are helium (He), Argon (Ar), Neon (Ne) Krypton (Kr), Radon (Rn) and Xenon (Xe). Noble gases conduct electricity. They are fluorescent, odorless and colorless. Noble gases are used a maintain stable elements in a constant and safe environment.
Enzymes are biological molecules (typically proteins) that significantly speed up the rate of virtually all of the chemical reactions that take place within cells.
33% is the unknown concentration of the tube.
Explanation:
Concentration of stock of windex = 50%
concentration of bacteria = 500 microliter
nutrient broth = 1000 micro litre +500 microlitre of windex
concentration of bacteria is the volume of bacteria present in nutrient broth culture.
total volume in the tube is 1000
50% is the concentration of tube of bacteria and broth before adding windex.
After adding windex of 50 % concentration and the volume is 500 microliter which is only 250 microliter of windex rest is water.
33% is the concentration of the tube, which means it has 33% of bacteria in 1500 ml of solution.
