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. ulas and Chemical Equations
Topic 5: Chemical form

5. Empirical formula: Determining and recognizing empirical formulas
1. Which formula is an empirical formula?
1) CH 2) C2H2 3) C2H4 4) C4H8

2. Which formula is an empirical formula? 3) H2O 4) H2O2
1) C2H6

2) C4 H10

3. An example of an empirical formula is
1) C4H10 2) C6H12O6 3) HC2H3O2 4) CH2O
4. Which formula is an empirical formula?
1) H2CO3 2) H2C2O4 3) CH3COOH 4) CH2OHCH2OH
1) C5H6 Teacher Preview Copy
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5. Which represents an empirical formula and a molecular formula?
1) P2O5 2) N2O4 3) C3H6 4) C6H12O6

6. Which compound has the same molecular and empirical formula?
1) C2H4 2) C3H6 3) CH4 4) H2O2

7. Which formula is both an empirical formula and a molecular formula for a known substance?
1) C6H12O6 2) C12H22O11 3) P4H10 4) P2O2

6. Empirical and molecular formulas: Relating empirical to molecular formula
1. What is the empirical formula of a compound whose molecular formula is P4H10 ?

1) PO 2) PO2 3) P2O5 4) P8O20

2. What is the empirical formula of a compound with the molecular formula of C6H10?
1) C2H5 2) C3H5 3) C5H3 4) C12H20

3. What is the empirical formula of C12H22O11 ?

1) C12H22O11 2) C6H11O11 3) C3H6O3 4) C22H48H22

4. The molecular formula of a compound is represented by X3Y6. What is the empirical formula of
this compound?
1) X3Y 2) X2Y 3) XY2 4) XY3

5. The empirical formula of a compound is CH3. The molecular formula of this compound could be
1) CH4 2) C2H2 3) C2H3 4) C2H6

6. Which of the following molecular formulas could have the empirical formula C2H3 ?
2) C4H6 3) C8H20 4) CH3
7. Which compound has the empirical formula CH ? 4) C3H8

2) C2H4

1) CH4
3) C6H6

8. Which molecular compound has the empirical formula of CH2O ? 4) HCOOH
1) CH3COOH

2) CH3OH
3) CH3CH2OH

9. Which two compounds have the same empirical formula?
1) C2H2 and C2H4 2) CH2 and C3H8 3) HO and H2O 4) NO2 and N2O4

10. Which molecular formula is correctly paired with its empirical formula?
1) CO2 and CO 2) C2H2 and C4H4 3) PO2 and P2O4 4) P4O10 and PO5

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