# Ch (2) : Calculations With Chemical Formulas And Equations

15 Questions | Total Attempts: 227  Settings  QUIZ FOR (( calculations with chemical formulas and equations )) Faculty of Engineering, Zagazig University BY &

• 1.
Percentage of Magnesium [Mg] in Magnesium sulfate [MgSO4] Given Atomic Weights:  Mg = 24  .   S = 32   .  O = 16
• A.

40

• B.

20

• C.

12

• D.

60

• 2.
Balance the following equation: Mg3N2 + H2O  Mg(OH)2 + NH3
• A.

Mg3N2 + 6H2O --> 3Mg(OH)2 + 2NH3

• B.

Mg3N2 + 6H2O --> 3Mg(OH)2 + NH3

• C.

Mg3N2 + 2H2O --> Mg(OH)2 + NH3

• D.

Mg3N2 + 3H2O --> 3Mg(OH)2 + 2NH3

• 3.
Calculate the mass % of carbon in carbon monoxide.
• 4.
A reaction that produces crude iron from iron ore is shown below: Fe2O3 (s) + 3CO (g 2Fe (s) + 3CO2 (g) How many moles of iron could be produced from the reaction of 10 mol Fe2O3 and 25 mol of CO?
• A.

10 mol

• B.

25 mol

• C.

17 mol

• D.

20 mol

• E.

35 mol

• 5.
You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements
• A.

SO

• B.

SO2

• C.

SO4

• D.

SO3

• 6.
Given the following: 42.07% Na, 18.89% P, and 39.04% O, determine the empirical formula
• A.

NaPO2

• B.

Na2PO3

• C.

Na3PO4

• D.

NaPO4

• 7.
Styrene has the empirical formula CH, and there is 92.25% carbon and 7.75% hydrogen. If you have a molar mass of 104g/mol, what is the multiplier or factor to get the molecular formula?
• A.

6

• B.

2

• C.

4

• D.

8

• 8.
Al(OH)3 + 3HCl --> 3H2O + AlCl3 If you have 14.0 grams of aluminum hydroxide, how much aluminum chloride is produced?
• A.

14.0 g

• B.

17.9 g

• C.

23.9 g

• 9.
Al(OH)3 + 3HCl --> 3H2O + AlCl3 If you actually recovered 22.0 grams of aluminum chloride, what is the percent yield of the reaction?
• A.

100%

• B.

92%

• C.

69%

• 10.
What is the percentage of oxygen in carbon dioxide? (CO2)
• 11.
Empirical Formula: 39.8% K, 27.8% Mn, 32.5% O
• A.

N3,Mn,5O

• B.

K2,Mn,O4

• C.

Mn3,K,O7

• D.

O10,Mn,5K

• 12.
The simplest formula of a substance shows
• A.

the actual number of atoms of each element in one molecule of a substance.

• B.

the elements that make up one molecule of the substance and the simplest whole number ratio between the atoms.

• C.

the number of molecules in a sample of the substance.

• D.

the molecular mass of the substance.

• 13.
A compound is found to have a molecular mass of 90 atomic mass units and simplest formula of C2H5O. The molecular formula of the substance is: (Atomic mass of C = 12 amu, H = 1 amu, O = 16 amu)
• A.

C3H6O3

• B.

C4H26O

• C.

C4H10O2

• D.

C5H14O

• 14.
How many grams of oxygen are in one mole of calcium carbonate, CaCO3? (Atomic mass of O = 16 amu.)
• A.

16 grams

• B.

32 grams

• C.

48 grams

• D.

64 grams

• 15.
The ionic compound containing Fe3+ and SO42- would have the formula
• A.

FeSO4

• B.

Fe2SO4

• C.

Fe2(SO4)3

• D.

Fe3(SO4)2

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