Live Education Quiz

1. 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

2. Ming has 0.5 moles of water (H2O). He wants to calculate the mass of water. The molar mass of water is 18 g/mol. What is the mass?

A 6 g

B 9 g

C 18 g

D 36 g

3. To convert mass into moles, we divide by:

A Avogadro’s number

B Atomic mass

C Density

D Volume

4. Emma is studying the structural formula of water. She knows that water has a bent structure. Which of the following is a structural formula for water?

A H2O

B H-O-H

C HO

D O-H-H

5. Empirical formula shows:

A Actual number of atoms

B Simplest whole number ratio

C Total mass of compound

D Structural arrangement

6. 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

7. The formula mass of NaCl is:

A 23 u

B 35.5 u

C 58.5 u

D 46 u

8. 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

9. David is calculating the number of atoms in 2 moles of oxygen gas (O2). How many atoms of oxygen are there?

A 1.204 × 10^24 atoms

B 2.408 × 10^24 atoms

C 3.011 × 10^23 atoms

D 6.022 × 10^23 atoms

10. Patricia is exploring ionic equations. She writes the complete ionic equation for a reaction. What is the difference between a molecular equation and an ionic equation?

A Ionic equation shows all ions, molecular equation shows complete compounds

B Molecular equation shows all ions, ionic equation shows complete compounds

C Both are identical

D Ionic equation is for solids only

11. Avogadro’s number is:

A 3.01 × 10^23

B 6.02 × 10^22

C 6.02 × 10^23

D 1.66 × 10^-24

12. 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

13. 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

14. 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

15. Hina is learning about Avogadro's number. She wants to know how many atoms are in one mole of carbon. What is the number?

A 6.022 × 10^23 atoms

B 12.044 × 10^23 atoms

C 3.011 × 10^23 atoms

D 1.204 × 10^24 atoms

16. Julia is studying gram formula mass. She wants to find the gram formula mass of CaCl2. (Ca=40, Cl=35.5)

A 75.5 g

B 111 g

C 90.5 g

D 120 g

17. Rachel is calculating the number of moles in 18 grams of water. The molar mass of water is 18 g/mol. How many moles does she have?

A 0.5 moles

B 1 mole

C 1.5 moles

D 2 moles

18. How many moles are present in 36 g of water?

A 1

B 2

C 3

D 4

19. George has 2 moles of water (H2O). He wants to calculate the number of water molecules. How many molecules does he have?

A 1.204 × 10^24 molecules

B 6.022 × 10^23 molecules

C 3.011 × 10^23 molecules

D 1.806 × 10^24 molecules

20. David is studying an ionic compound, NaCl. He wants to calculate the formula mass. He knows Na=23 and Cl=35.5. What is the formula mass of NaCl?

A 58.5 g/mol

B 60.5 g/mol

C 55.5 g/mol

D 50.0 g/mol

21. 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

22. Stoichiometric calculations are based on:

A Unbalanced equations

B Balanced equations

C Word equations

D Skeletal equations

23. Which quantity links mass and number of particles?

A Density

B Mole

C Volume

D Pressure

24. Which concept helps in converting particles to mass?

A Atomic number

B Mole concept

C Valency

D Density

25. Uma is calculating the gram atomic mass of sodium. She knows that the atomic mass of Na is 23 amu. What is the gram atomic mass of sodium?

A 23 g

B 46 g

C 11.5 g

D 6.022 × 10^23 g

26. Rachel is studying molecular and structural formulas. She knows that the molecular formula gives the actual number of atoms, but not the arrangement. Which formula shows the arrangement of atoms in a molecule?

A Empirical formula

B Molecular formula

C Structural formula

D Formula mass

27. The chemical formula shows:

A Only elements

B Types and number of atoms

C Mass of compound

D Volume of compound

28. Limiting reagent determines the:

A Rate of reaction

B Amount of product

C Color change

D Temperature change

29. Zara has 5 moles of NaCl. How many formula units of NaCl does she have?

A 3.011 × 10^24 formula units

B 6.022 × 10^23 formula units

C 1.204 × 10^24 formula units

D 1.806 × 10^24 formula units

30. George is calculating the number of moles in 44 g of CO2. The molar mass of CO2 is 44 g/mol. How many moles?

A 0.5 moles

B 1 mole

C 1.5 moles

D 2 moles

Chapter 6: Stoichiometery

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