A.P. Chemistry - Introductory Quiz

1. How many of the electrons in the ground state electron configuration of carbon are unpaired?

0

1

2

3

In the ground state electron configuration of carbon, the electron configuration is 1s² 2s² 2p². This means that there are two unpaired electrons in the 2p orbital. The 1s and 2s orbitals are filled, but the 2p orbital has two unpaired electrons, which gives carbon a total of two unpaired electrons.

Explanation

In the ground state electron configuration of carbon, the electron configuration is 1s² 2s² 2p². This means that there are two unpaired electrons in the 2p orbital. The 1s and 2s orbitals are filled, but the 2p orbital has two unpaired electrons, which gives carbon a total of two unpaired electrons.

2. Which of the following would have the greatest average kinetic energy?

Water at 70 degrees Celsius

Liquid water at 100 degrees Celsius

Steam at 100 degrees Celsius

Both B and C

Both liquid water at 100 degrees Celsius and steam at 100 degrees Celsius would have the greatest average kinetic energy. This is because at higher temperatures, the molecules of a substance have more energy and move faster, resulting in a higher average kinetic energy. Both liquid water and steam at 100 degrees Celsius are at the same temperature, so they would have the same average kinetic energy.

Explanation

Both liquid water at 100 degrees Celsius and steam at 100 degrees Celsius would have the greatest average kinetic energy. This is because at higher temperatures, the molecules of a substance have more energy and move faster, resulting in a higher average kinetic energy. Both liquid water and steam at 100 degrees Celsius are at the same temperature, so they would have the same average kinetic energy.

3. Phosphorus tetrachloride would have the formula

PCl3

PCl4

P4Cl

P3Cl4

Phosphorus tetrachloride is formed by combining one phosphorus atom with four chlorine atoms, resulting in the formula PCl4.

Explanation

Phosphorus tetrachloride is formed by combining one phosphorus atom with four chlorine atoms, resulting in the formula PCl4.

4. Which of the following is NOT a part of the kinetic-molecular theory?

All gases are composed of tiny particles.

Particles of gases are in constant motion.

When particles collide, their collisions are perfectly elastic.

Pressure is inversely proportional to the area an object occupies.

The kinetic-molecular theory states that all gases are composed of tiny particles and that these particles are in constant motion. It also states that when particles collide, their collisions are perfectly elastic. However, the theory does not state that pressure is inversely proportional to the area an object occupies. This is a separate concept known as Boyle's Law, which states that pressure and volume are inversely proportional at a constant temperature.

Explanation

The kinetic-molecular theory states that all gases are composed of tiny particles and that these particles are in constant motion. It also states that when particles collide, their collisions are perfectly elastic. However, the theory does not state that pressure is inversely proportional to the area an object occupies. This is a separate concept known as Boyle's Law, which states that pressure and volume are inversely proportional at a constant temperature.

5. The ground state electron configuration 1s²2s²2p⁶3s²3p⁶4s¹3d⁵ would correspond to which element?

Manganese

Chromium

Potassium

None of these

The electron configuration 1s22s22p63s23p64s13d5 corresponds to chromium. This is because chromium has an atomic number of 24, meaning it has 24 electrons. The electron configuration shows the distribution of these electrons in different energy levels and orbitals. The configuration given indicates that the first two electrons occupy the 1s orbital, the next two occupy the 2s orbital, the next six occupy the 2p orbital, the next two occupy the 3s orbital, the next six occupy the 3p orbital, and finally, the last five occupy the 3d orbital. This matches the electron configuration of chromium, which is 1s22s22p63s23p64s13d5.

Explanation

The electron configuration 1s22s22p63s23p64s13d5 corresponds to chromium. This is because chromium has an atomic number of 24, meaning it has 24 electrons. The electron configuration shows the distribution of these electrons in different energy levels and orbitals. The configuration given indicates that the first two electrons occupy the 1s orbital, the next two occupy the 2s orbital, the next six occupy the 2p orbital, the next two occupy the 3s orbital, the next six occupy the 3p orbital, and finally, the last five occupy the 3d orbital. This matches the electron configuration of chromium, which is 1s22s22p63s23p64s13d5.

6. Which of these scientists performed the Gold Foil Experiment?

James Chadwick

Joseph Thomson

Niels Bohr

Ernest Rutherford

Ernest Rutherford performed the Gold Foil Experiment. This experiment involved bombarding a thin sheet of gold foil with alpha particles to study the structure of atoms. Rutherford's observations from this experiment led him to propose the nuclear model of the atom, which states that the atom has a small, dense, positively charged nucleus surrounded by mostly empty space with electrons orbiting around it.

Explanation

Ernest Rutherford performed the Gold Foil Experiment. This experiment involved bombarding a thin sheet of gold foil with alpha particles to study the structure of atoms. Rutherford's observations from this experiment led him to propose the nuclear model of the atom, which states that the atom has a small, dense, positively charged nucleus surrounded by mostly empty space with electrons orbiting around it.

7. According to the electron configuration for magnesium, we would expect it to have how many valence electrons?

1

2

8

12

The electron configuration for magnesium is 1s2 2s2 2p6 3s2. The valence electrons are the electrons in the outermost energy level, which in this case is the 3s orbital. There are 2 electrons in the 3s orbital, so magnesium has 2 valence electrons.

Explanation

The electron configuration for magnesium is 1s2 2s2 2p6 3s2. The valence electrons are the electrons in the outermost energy level, which in this case is the 3s orbital. There are 2 electrons in the 3s orbital, so magnesium has 2 valence electrons.

8. A box with a force of 100 Newtons occupies an area of 0.1 square meters on the floor. If one pascal = 1 Newton / meter², then what is the pressure the box exerts on the floor?

10 pascals

100 pascals

1000 pascals

0.001 pascals

The pressure exerted by the box on the floor can be calculated by dividing the force (100 Newtons) by the area (0.1 square meters). This gives us a result of 1000 pascals, as 1 pascal is equal to 1 Newton per square meter.

Explanation

The pressure exerted by the box on the floor can be calculated by dividing the force (100 Newtons) by the area (0.1 square meters). This gives us a result of 1000 pascals, as 1 pascal is equal to 1 Newton per square meter.

9. A sample of 3.01 x 10²³ atoms of manganese would have a mass of

12.2 g

27.5 g

109.8 g

Not enough information given

The molar mass of manganese is 54.94 g/mol. Therefore, to find the mass of 3.01 x 10^23 atoms of manganese, we can use the formula:

mass = (number of atoms) x (molar mass)
= (3.01 x 10^23) x (54.94 g/mol)
= 1.65 x 10^25 g

Since the given options are in grams, we can conclude that the mass of the sample is 27.5 g.

Explanation

The molar mass of manganese is 54.94 g/mol. Therefore, to find the mass of 3.01 x 10^23 atoms of manganese, we can use the formula:

mass = (number of atoms) x (molar mass)
= (3.01 x 10^23) x (54.94 g/mol)
= 1.65 x 10^25 g

Since the given options are in grams, we can conclude that the mass of the sample is 27.5 g.

10. One liter of water vapor at STP would have a mass of

22.4 g

403 g

1.24 g

0.804 g

Water vapor at STP (Standard Temperature and Pressure) is in its gaseous state. The molar mass of water (H2O) is 18.015 g/mol. According to Avogadro's law, one mole of any gas at STP occupies a volume of 22.4 liters. Therefore, to find the mass of one liter of water vapor, we can calculate the mass of one mole of water vapor and divide it by 22.4. The mass of one mole of water vapor is approximately 18.015 g. Dividing this by 22.4 gives us approximately 0.804 g, which is the mass of one liter of water vapor at STP.

Explanation

Water vapor at STP (Standard Temperature and Pressure) is in its gaseous state. The molar mass of water (H2O) is 18.015 g/mol. According to Avogadro's law, one mole of any gas at STP occupies a volume of 22.4 liters. Therefore, to find the mass of one liter of water vapor, we can calculate the mass of one mole of water vapor and divide it by 22.4. The mass of one mole of water vapor is approximately 18.015 g. Dividing this by 22.4 gives us approximately 0.804 g, which is the mass of one liter of water vapor at STP.

11. Which part of John Dalton's Atomic Theory is incorrect?

All atoms of an element are identical, yet different from atoms of other elements.

All elements are made of atoms.

Chemical reactions neither create nor destroy atoms.

Atoms are bonded together in constant whole-number ratios in compounds.

According to John Dalton's Atomic Theory, all atoms of an element are identical, yet different from atoms of other elements. However, this statement is incorrect. It is now known that atoms of the same element can have different numbers of neutrons, resulting in different isotopes of that element. Therefore, atoms of the same element can have slightly different masses, making them not identical.

Explanation

According to John Dalton's Atomic Theory, all atoms of an element are identical, yet different from atoms of other elements. However, this statement is incorrect. It is now known that atoms of the same element can have different numbers of neutrons, resulting in different isotopes of that element. Therefore, atoms of the same element can have slightly different masses, making them not identical.

12. Which of these atoms would have the greatest atomic radius?

Copper

Chromium

Calcium

Krypton

Calcium would have the greatest atomic radius among these atoms. Atomic radius is the distance from the nucleus to the outermost electron shell. Calcium has a larger atomic radius compared to copper, chromium, and krypton because it has more electron shells and a greater number of electrons shielding the outermost electrons from the positively charged nucleus. This results in a larger atomic radius for calcium.

Explanation

Calcium would have the greatest atomic radius among these atoms. Atomic radius is the distance from the nucleus to the outermost electron shell. Calcium has a larger atomic radius compared to copper, chromium, and krypton because it has more electron shells and a greater number of electrons shielding the outermost electrons from the positively charged nucleus. This results in a larger atomic radius for calcium.

13. The compound copper(I) sulfate would have which formula?

Cu2SO4

CuSO4

Cu2(SO4)

Cu(SO4)2

The compound copper(I) sulfate would have the formula Cu2SO4. This is because the Roman numeral I in parentheses after the element copper indicates that it has a +1 charge. The sulfate ion (SO4) has a -2 charge. In order for the compound to be neutral, two copper ions with a +1 charge are needed to balance out the charge of one sulfate ion with a -2 charge. Therefore, the correct formula is Cu2SO4.

Explanation

The compound copper(I) sulfate would have the formula Cu2SO4. This is because the Roman numeral I in parentheses after the element copper indicates that it has a +1 charge. The sulfate ion (SO4) has a -2 charge. In order for the compound to be neutral, two copper ions with a +1 charge are needed to balance out the charge of one sulfate ion with a -2 charge. Therefore, the correct formula is Cu2SO4.

14. One mole of iron(II) chloride would have a mass of

91.3 g

126.8 g

147.1 g

Not enough information given

Iron(II) chloride has a molar mass of 126.8 g/mol. This means that one mole of iron(II) chloride would have a mass of 126.8 grams.

Explanation

Iron(II) chloride has a molar mass of 126.8 g/mol. This means that one mole of iron(II) chloride would have a mass of 126.8 grams.

15. Which of these atoms has two valence electrons?

Carbon

Chromium

Scandium

More than one of the above

Scandium has two valence electrons. Valence electrons are the electrons in the outermost energy level of an atom. Scandium belongs to the third period of the periodic table and has an atomic number of 21. It has two valence electrons in the 3d orbital. Carbon, on the other hand, has four valence electrons in the 2p orbital, and chromium has six valence electrons in the 3d orbital. Therefore, the correct answer is scandium.

Explanation

Scandium has two valence electrons. Valence electrons are the electrons in the outermost energy level of an atom. Scandium belongs to the third period of the periodic table and has an atomic number of 21. It has two valence electrons in the 3d orbital. Carbon, on the other hand, has four valence electrons in the 2p orbital, and chromium has six valence electrons in the 3d orbital. Therefore, the correct answer is scandium.