Why is it important to dispose of or use elements properly ?

If they aren't disposed of safely, those chemicals can pose a safety hazard to people, animals and the environment. In addition to contaminating soil, hazardous wastes can pollute the air and leach into water sources. ... They are considered hazardous because they also contain lead.

Explanation:

Carrying out investigations in a responsible way can reduce pollution and waste. It can also ensure that natural resources and other materials will be available for future generations. reusing: Glass beakers can be washed and used again.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

b. accuracy of the data matters alot more than its number of digits, organization or amount of detail. quantitative observation is more accepted than the qualitative observation.