Since there are 23 days and 24 hours in each day, you multi-ply them and get 552 hours. Since each hours is 60 minutes, 552*60 is 33120 minutes. Since one minute is 60 seconds, 60*33120 is 1,987,200 seconds. Therefore, there are 1,987,200 seconds in 23 days.
This problem is asking for the percent by mass of hydrogen in hydrofluoric acid. At the end, the answer turns out to be D. 5% as shown below:
<h3>Percent compositions:</h3>
In chemistry, percent compositions are used for us to know the relative amount of a specific element in a compound. In order to do so for hydrogen, we use the following formula, which can also be applied to any other element in a given compound:

Where
stands for the atomic mass of hydrogen and
for the molar mass of hydrofluoric acid. In such a way, we plug in the atomic masses of hydrogen (1.01 g/mol) and fluorine (19.0 g/mol) to obtain:

Learn more about percent compositions: brainly.com/question/12247957
Solution: Sentence D is a scientific statement.
Scientific statement is a statement that defines the science behind any situation. There should be any experimental result or observation to state any scientific statement. Also, the statement should be accepted by considering other scientific aspects.
Here, statement A can not be a scientific statement as different aromas of cooked food are liked by different people. Any one can find aroma of cooked food in copper better than the ceramic pot.
Thus, the statement can be proved wrong easily.
Statement B can not be a scientific statement as people can find the taste of normal water (without ice cubes) better than the ice cold water.
Statement C is not a scientific statement as there is no science behind watching baseball or ice hockey, it depends on the liking of today's people.
Statement D is a scientific statement because this can be scientifically proved.
Metal rusts when it oxidized around moisture.
Answer:
62.5 mg
Explanation:
Just multiply the original amount by 1/2 three times:
500 mg x 1/2 x 1/2 x 1/2 = 62.5 mg