Avogadro's number is significant because it:

A. Represents the number of atoms in 12 grams of carbon-12.

B. Relates the macroscopic world to the atomic/molecular level.

C. Defines the number of electrons in one mole of electrons.

D. Represents the number of molecules in 1 gram of water.

Which of the following is the correct unit for molar mass?

A. g/mol

B. mol/g

C. g

D. mol

To determine the molar mass of an element using periodic table data, one should:

A. Take the atomic number of the element.

B. Take the number of neutrons in the element.

C. Take the relative atomic mass of the element.

D. Take the number of electrons in the element.

If you have 0.5 moles of sodium (Na), how many atoms of sodium do you have?

A. 0.5 x 6.02 x 10^23

B. 0.5 + 6.02 x 10^23

C. 0.5 - 6.02 x 10^23

D. 0.5 / 6.02 x 10^23

The mole concept is crucial in stoichiometry because:

A. It allows for the counting of individual atoms and molecules.

B. It defines the mass of one mole of a substance.

C. It provides a bridge between the atomic and macroscopic worlds.

D. It represents the number of electrons in an atom.

a) Define Avogadro's number and explain its significance in relating the macroscopic world to the atomic/molecular level. [3]

b) How can one determine the molar mass of an element using periodic table data? [2]

a) Differentiate between the terms 'mole' and 'molar mass'. [3]

b) If you have 12 grams of carbon, how many moles of carbon atoms do you have? [2]

a) Describe the importance of the mole concept in stoichiometry. [3]

b) If a chemical reaction requires 2 moles of hydrogen gas (H2) to produce 1 mole of water (H2O), how many moles of hydrogen gas would be needed to produce 5 moles of water? [2]

a) What is the significance of Avogadro's number in the context of the mole concept? [3]

b) Given that the atomic mass of magnesium is approximately 24.31, determine its molar mass. [2]

c) How many atoms are present in 0.5 moles of magnesium? [3]

a) Define the terms 'element', 'compound', and 'mixture'. [3]

b) How does the atomic theory explain the composition of compounds? [3]

c) If 3 moles of water (H2O) are decomposed, how many moles of hydrogen gas (H2) and oxygen gas (O2) would be produced? [3]

Which of the following represents Avogadro's number?

A. 6.02 x 10^22

B. 6.02 x 10^24

C. 6.02 x 10^23

D. 6.02 x 10^21

If you have 56 grams of iron (Fe), how many moles of iron do you have? (Given: Molar mass of Fe = 56 g/mol)

A. 1 mole

B. 2 moles

C. 0.5 moles

D. 56 moles

Which of the following is NOT a direct application of the mole concept?

A. Determining the number of atoms in a sample.

B. Predicting the outcome of a chemical reaction.

C. Measuring the temperature of a substance.

D. Calculating the mass of reactants required for a reaction.

The number of particles in 2 moles of carbon dioxide (CO2) is:

A. 6.02 x 10^23

B. 1.204 x 10^24

C. 3.01 x 10^23

D. 12.04 x 10^23

If you have 32 grams of oxygen (O2), how many molecules of oxygen do you have? (Given: Molar mass of O2 = 32 g/mol)

A. 6.02 x 10^23

B. 3.01 x 10^23

C. 1.204 x 10^24

D. 12.04 x 10^23

a) Describe the postulates of the atomic theory. [4]

b) How does the random motion of particles serve as evidence for the existence of atoms and molecules? [3]

c) Convert 120 grams of carbon into moles. Given the molar mass of carbon is approximately 12.01 g/mol. [2]

a) What is the relationship between gas pressure and particle motion? [3]

b) Define and differentiate between melting and sublimation. [3]

c) If a substance has a molar mass of 32 g/mol and you have 64 grams of it, how many moles do you possess? [2]

a) Define Avogadro's number and explain its significance in the mole concept. [3]

b) If the atomic mass of sodium is approximately 23, determine its molar mass. [2]

c) How many atoms are present in 2 moles of sodium? [3]

d) Why is the mole concept crucial in stoichiometry? [3]

a) Describe the differences in particle arrangement and energy in solids, liquids, and gases. [4]

b) Give an example of a substance in each state and the conditions for their existence. [3]

c) Convert 44 grams of carbon dioxide into moles. Given the molar mass of carbon dioxide is approximately 44 g/mol. [2]

d) What evidence does the random motion of particles provide about the existence of atoms and molecules? [3]

a) What is the definition of matter? [2]

b) Differentiate between elements, compounds, and mixtures. [4]

c) If 3 moles of water (H2O) are decomposed, how many moles of hydrogen gas (H2) and oxygen gas (O2) would be produced? [3]

d) Describe the postulates of the atomic theory. [4]