Posted by **Bryan** on Sunday, February 11, 2007 at 3:48pm.

Classify each of these statements as always true, sometimes true, or never true.

7____AT____It is necessary to know the formula of a compound in order to calculate its percent composition.

8___ST_____If the percent by mass of carbon in methane, CH4, is 75%, then 100 grams of methane contain 25.0 grams of hydrogen.

9____AT____The formula for methane, CH4, is both a molecular and an empirical formula.

10____NT___The empirical formula for glucose, C6H23O6, is C2H4O2.

7. I may not understand this question very well but I can calculate the percent composition if I know the grams of A that combine with the grams of B as well as if I know the formula.

8. You need to rethink this. If CH4 is 75% C it must be 25% H and 100 g CH4 will contain 25g H. If it is sometimes true, when is it not true?

9. I go along.

10. Glucose is C6H12O6; therefore, the empirical formula is CH2O. Since the incorrect formula is given for glucose I don't know how to answer this.

Help on Completion.

The Percent by mass of an element in a compound is the number of grams of the element per _____g of the compound, multiplied by 100%.

## Answer this Question

## Related Questions

- Math - a.)If ABCD is a parallelogram, then ABCD is (always true, sometimes true...
- Chemistry (Check) - Classify each of these statements as always true, sometimes ...
- Chemistry check - Can someone make sure I have the right answer. The question is...
- geometry - Is it always true, sometimes true, or never true that the centroid is...
- math - In order for the percent composition of a compound to be calculated, the ...
- Chemistry (Check) - Classify each of these statements as always true, sometimes ...
- math - Determine whether the statement is always true, sometimes true, or never ...
- Algebra - A positive integer minus a positive integer is always positive. This ...
- math - When solving for the percent composition of a given compound, the percent...
- chemistry - 1.to calculate the percent by massof an element in a known compound...

More Related Questions