Hello there.
<span>Substances that cannot be broken down into simpler substances are called ____________.
Answer: It is called an Element.
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The OSHA limit for STEL-TWA is 2ppm and the PEL-STEL value is 4ppm to the exposure to nitric acid.
OSHA refers to Occupational Safety and Health Administration has adopted standard values for the exposure to harmful and hazardous chemicals so that the safety of workers and testing animals could be ensured.
Here, STEL-TWA stands for Short Term Exposure Limit - Time-Weighted average, and PEL-STEL stands for Permissible Exposure Limit- Short Term Exposure Limit.
This is usually set up in industries to ensure the safety of the workers and the maximum exposure short-term time limit is 15min and 2ppm for STEL-TWA and 4 ppm for PEL-STEL.
To know more about Industrial Safety measures, click below:
brainly.com/question/14367881
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Bromine in a period frim left to right electronegativity increases
Answer:
1/ Using the first letter of the name of the elements.
2/ If the name of two or more elements begins with the same letter,the second letter of their name is also taken with first letter.
3/ Symbols are made by using the letters of the name of elements in other languages also.
