Always remember that a compound can be separated into simpler substances by chemical methods/reactions. While elements cannot be broken down into simpler substances by chemical reactions. You can do a flame test and spectrum analysis to determine whether a solid material is an element or a compound. Check the boiling and/or melting point, color or density. Also check the solid material’s reaction with oxygen, hydrogen, calcium, or various acids. Examine and study its physical chemistry. The element(s) that may be present may be identified by checking the absorption edges from an x-ray spectrum.
C
It is a idea which no kind of evidence is allowed to prove wrong
Answer:

Explanation:
Percent yield is the ratio of the amount actually produced to how much could theoretically be produced. It is found using this formula:

For this reaction, the theoretical or expected yield is 325.0 grams. The actual yield is 123.8 grams.

Divide.


Round to the nearest hundredth. The 9 in the hundredth place tells us to round the 0 to a 1 .

The percent yield is about <u>38.1%</u>
Answer:
Molar mass of Na2HPO4=141.96, of Na2HPO4. 12H2O = 358.14: so to get the same 0.4 M: 28.65/358.14*141.96 g, add water until you reach 200ml , dissolve all solid and then filter to make sterile.
Explanation: