1 Stoichiometry is the study of: A Atomic structure B Chemical calculations C Chemical bonding D States of matter
2 Nora is calculating the formula mass of CaCO3. She knows Ca=40, C=12, O=16. What is the formula mass? A 100 g/mol B 84 g/mol C 112 g/mol D 96 g/mol
3 Patricia is balancing the equation: Al + O2 → Al2O3. What is the correct balanced equation? A 4Al + 3O2 → 2Al2O3 B 2Al + O2 → Al2O3 C Al + O2 → Al2O3 D 3Al + 2O2 → Al2O3
4 Gram atomic mass is equal to: A Atomic number in grams B Atomic mass in grams C Mass number in grams D Neutron number in grams
5 Victor is calculating the gram molecular mass of nitrogen gas (N2). He knows N=14. What is the gram molecular mass of N2? A 14 g B 28 g C 56 g D 7 g
6 Ming is studying empirical and molecular formulas. He knows that the empirical formula is the simplest ratio of atoms, while the molecular formula is the actual number. For a compound with empirical formula CH and molecular mass 78, what is the molecular formula? (C=12, H=1) A C6H6 B C2H2 C C3H3 D C4H4
7 Which law forms the basis of stoichiometry? A Law of inertia B Law of conservation of mass C Law of motion D Law of gravitation
8 Hina is studying gram atomic mass. She knows that the gram atomic mass of an element is the mass of one mole of atoms of that element. What is the gram atomic mass of oxygen? A 8 g B 16 g C 24 g D 32 g
9 Tina is calculating the mass of 0.25 moles of NaCl. The molar mass of NaCl is 58.5 g/mol. What is the mass? A 14.625 g B 29.25 g C 58.5 g D 7.3125 g
10 Khalid is comparing gram atomic mass and gram molecular mass. He knows that gram atomic mass applies to elements and gram molecular mass applies to compounds. What is the difference between them? A Gram atomic mass is for elements, gram molecular mass is for compounds B Gram atomic mass is for compounds, gram molecular mass is for elements C Both are the same D Gram atomic mass is larger
11 The substance left after reaction is called: A Limiting reagent B Excess reagent C Product D Catalyst
12 Lara has 10 grams of calcium (Ca). She wants to calculate the number of moles. The atomic mass of Ca is 40 g/mol. How many moles does she have? A 0.25 moles B 0.5 moles C 1.0 moles D 2.0 moles
13 Yusuf is calculating the formula mass of Al2O3. He knows Al=27 and O=16. What is the formula mass? A 78 g/mol B 102 g/mol C 96 g/mol D 132 g/mol
14 Limiting reagent determines the: A Rate of reaction B Amount of product C Color change D Temperature change
15 Julia is studying ionic equations. She knows that in an ionic equation, spectator ions are ions that do not participate in the reaction. What happens to spectator ions in an ionic equation? A They are removed from the equation B They are written as separate ions C They are combined with other ions D They are written as solids
16 Gram molecular mass is the mass of: A One molecule in grams B One mole of molecules C One atom in grams D One ion in grams
17 Ahmed is analyzing a compound and finds that it contains 40% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. He wants to find the simplest whole-number ratio of atoms in the compound. What is this ratio called? A Molecular formula B Empirical formula C Structural formula D Ionic formula
19 Waseem is studying the difference between gram molecular mass and gram formula mass. He knows that gram molecular mass is for covalent compounds, while gram formula mass is for ionic compounds. Which is true? A Both are the same B Gram molecular mass is for ionic, gram formula mass is for covalent C Gram molecular mass is for covalent, gram formula mass is for ionic D Gram formula mass is only for acids
21 To convert moles into particles, we multiply by: A Atomic mass B Molecular mass C Avogadro’s number D Density
22 One mole of O2 contains how many atoms? A 6.02 × 10^23 B 12.04 × 10^23 C 3.01 × 10^23 D 1.00 × 10^23
24 Waseem is studying the empirical formula of a compound. He analyzes a compound and finds its mass composition: 32% sulfur and 48% oxygen. What is the empirical formula? (S=32, O=16) A SO B SO2 C SO3 D S2O3
25 Which concept helps in converting particles to mass? A Atomic number B Mole concept C Valency D Density
26 Oliver is balancing a chemical equation. He has the equation: H2 + O2 → H2O. What is the coefficient of water when the equation is balanced? A 1 B 2 C 3 D 4
27 Molecular formula shows: A Simplest ratio of atoms B Percentage composition C Actual number of atoms D Ionic charge
28 Which quantity remains fixed for one mole of any substance? A Mass B Volume C Number of particles D Density
29 Tina is balancing the equation: Fe + O2 → Fe2O3. She starts with 4 Fe atoms and 3 O2 molecules. What is the balanced equation? A 4Fe + 3O2 → 2Fe2O3 B 2Fe + O2 → Fe2O3 C 3Fe + 2O2 → Fe3O4 D Fe + O2 → FeO