Secretary of State John Hay sent his Open Door Notes (1899-1900) to world powers to protect United States trading interests in China. The correct option among all the options that are given in the question is option "3". These notes were mainly in regards to providing equal opportunity for trades in China and also respecting China's sovereignty, territorial integrity and administration. The principles of operating in China was the same for the British as well as for the United States, but John Hay was the first person to give it a written form. After this the official policy of the United States was based on the written document during the first half of the 20th century.
Answer:

Explanation:
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In this case, according to the given information it turns out possible for us to realize that one mole of the given compound, Mg(ClO₄)₂, has one mole of Mg, two moles of Cl and eight moles of O; thus, we proceed as follows:

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Answer:
hypertonic solution
Explanation:
Hypertonic solution -
It is the solution, with more amount of solute than the solvent , is known as hypertonic solution.
Now, is some substance is immersed in such solution , the substance gets shrinked , because , the solvent from the substance moves out of it and moves to the hypertonic solution.
Hence, the pickles gets shrinked up , as they put in a hypertonic solution.
Answer:
11 protons
Explanation:
Sodium (Na)'s atomic number or proton number is 11, which means it contains 11 protons