It is softer than topaz and and it is softer than diamond (diamond has a Mohs hardness of 10, which is the highest value of the scale)
Answer:

Explanation:
Hello,
In this case, we can consider the following chemical reaction for the oxidation of copper which only occurs at high temperatures:

In such a way, for 0.032 grams of copper, the following grams of copper (II) oxide (black product) are yielded:

Therefore, the percent yield is:

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Answer:
1) 17.5 mL
Explanation:
Hello,
In this case, the reaction between sulfuric acid and potassium hydroxide is:

In such a way, we notice a 1:2 molar ratio between the acid and the base, therefore, at the equivalence point we have:

And in terms of concentrations and volumes:

Thus, we solve for the volume of acid:

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