Uploaded by Michele Culletto

Review Packet Math of Chemistry

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Name: ______________________
Period: ______________________
Date: _______________________
Review Packet: Math of Chemistry
Counting Atoms and Gram Formula Mass
Directions: ​count the atoms in each compound. Then solve for the gram formula mass
1. Na​2​CO​3
5. NH​4​C​2​H​3​O​2
2. Ca​3​(PO​4​)​2
6. Al​2​(CO​3​)​3
3. K​2​CrO​4
7. Pb(NO​3​)​2
4. BaCl​2
8. (NH​4​)​2​Cr​2​O​7
Unit 1: Math of Chemistry
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Name: ______________________
Period: ______________________
Date: _______________________
Determining Percent Composition
Directions: ​Determine the percent composition of the given element in the given compounds
9. % composition of O in CO​2
10. % composition of C in CH​2​0
11. % composition of S in H​2​SO​4
12. % composition of Cu in CuSO​4
13. % composition of Cl in CHCl​3
14. % composition of H in C​12​H​22​O​11
15. % composition of N in C​14​H​20​N​2​SO​4
Unit 1: Math of Chemistry
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Name: ______________________
Period: ______________________
Date: _______________________
Calculating Moles
Directions: ​Calculate the number of moles or grams in each element
16. How many moles are in 15 grams of lithium?
17. How many grams are in 2.4 moles of sulfur?
18. How many moles are in 22 grams of argon?
19. How many grams are in 88.1 moles of magnesium?
20. How many moles are in 2.3 grams of phosphorus?
21. How many grams are in 11.9 moles of chromium?
22. How many moles are in 9.8 grams of Calcium?
23. How many grams are in 238 moles of arsenic?
Directions: ​Calculate the molecular weights of the following compounds.
24. NaOH
27. H​3​PO​4
25. H​2​O
28. Mn​2​Se​7
26. MgCl​2
29. (NH​4​)SO​4
Unit 1: Math of Chemistry
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Name: ______________________
Period: ______________________
Date: _______________________
Finding Empirical and Molecular Formulas
Directions: ​Find the molecular or empirical formulas
30. Find the molecular formula for the compound with an empirical formula of C​2​H​3​ and a molar Mass of
189.0 g/mol. Show all work.
31. A compound has an empirical formula of CH​2​ and a molecular mass of 28 amu. What is the molecular
formula? Show all work.
32. Vitamin C has an empirical formula of C​3​H​4​O​3​ and a molecular mass of 176 amu. What is its molecular
formula? Show all work.
33. A compound has a molar mass of 90 grams per mole and the empirical formula CH​2​O. What is the
molecular formula of this compound?
a. C​2​H​4​O​2
c. C​3​H​6​O​3
b. C​4​H​8​O​4
d. CH​2​O
34. A substance has an empirical formula of CH2 and a molar mass of 56 grams per mole. The molecular
formula for this compound is:
a. C​8​H​4
c. C​4​H​8
b. CH​2
d. C​4​H​6
35. A compound has an empirical formula of HCO2 and a molecular mass of 90 grams per mole. What is
the molecular formula of this compound?
a. H​6​C​6​O​12
c. HCO
b. H​2​C​2​O​4
d. C​4​C​4​O​8
36. What is the molecular formula of a compound that has a molecular mass of 92 and an empirical formula
of NO2?
a. N​3​O​6
b. N​2​O​4
Unit 1: Math of Chemistry
c. NO​2
d. N​4​O​8
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Name: ______________________
Period: ______________________
Date: _______________________
Balancing Equations and Mole Ratios
Directions: ​Use the balanced chemical equations to answer the following questions.
37. 6HCl + Fe​2​O​3​ → 2 FeCl​3​ + 3 H​2​O
a. If 3 moles of HCl react in the above reaction, how many moles of FeCl​3​ would be produced?
b. If 6 moles of H2O were produced, how many moles of FeCl​3​ would be produced?
38. 2Al + 3S → Al​2​S​3
a. If 10 moles of Al react, how many moles of S would be needed?
b. If 1.0 moles of S are reacted, how much Al​2​S​3​ is produced?
39. 2C​2​H​2​ + 5O​2​ → 4CO​2​ + 2H​2​0
a. How many moles of CO2 are produced when 5.0 moles of C2H2 are reacted?
b. If 16 moles of Co2 are produced in the reaction, how many moles of O2 reacted?
40. H​2​ + Cl​2​ → 2NH​3
a. How many moles of hydrogen are needed to completely react with 2.5 moles of nitrogen?
Directions: ​Balance the following equations.
41. _____ NaBr + _____ H​3​PO​4​ → _____Na​3​PO​4​ + _____HBr
42. _____ Ca(OH)​2​ + _____Al​2​(SO​4​)​3​ → _____CaSO​4​ + _____ Al(OH)​3
43. _____ Mg + _____Fe​2​O​3​ → _____Fe + _____MgO
44. _____ C​2​H​4​ + _____ O​2​ → _____ CO​2​ + _____H​2​O
45. _____PbSO​4​ → _____PbSO​3​ + _____O​2
46. _____ NH​3​ + ______I​2​ → _____N​2​I​6​ + _____ H​2
47. _____ H​2​O + _____ SO​3​ → _____H​2​SO​4
48. _____ H​2​SO​4​ + _____ NH​4​OH → _____ H​2​O + _____ (NH​4​)​2​SO​4
Unit 1: Math of Chemistry
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