<u>Answer:</u> The chemical reaction for the synthesis reaction is given below.
<u>Explanation:</u>
Synthesis reaction is defined as a chemical reaction in which two small chemical substances combine together to form a single compound. The general equation for this chemical reaction follows:

For the reaction of calcium and oxygen combining together to form calcium oxide, the equation follows:

By Stoichiometry,
2 moles of calcium element combines together with 1 mole of oxygen gas to produce 2 moles of calcium oxide.
Hence, the chemical equation for the reaction is given above.
A physical change.
Physical change = can be reverted + doesn't change substance
Chemical = changes substance
Answer: There are 78.26 mL of a 0.0023M strontium hydroxide solution are needed to completely react 15.0 mL of 0.012M hydrochloric acid.
Explanation:
Given:
= 0.0023 M,
= ?
= 15.0 mL,
= 0.012 M
Formula used to calculate volume of strontium hydroxide solution is as follows.

Substitute the values into above formula as follows.

Thus, we can conclude that there are 78.26 mL of a 0.0023M strontium hydroxide solution are needed to completely react 15.0 mL of 0.012M hydrochloric acid.
Answer:

Explanation:
Hello there!
In this case, according to the given information of the solubility of copper chloride, as the maximum amount of this salt one can dissolve without having a precipitate, we infer that since just 73 grams are actually dissolved, the following amount will remain solid as a precipitate:

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