Question 1

A metal such as chromium in the body-centered cubic lattice has ________ atom(s) per unit cell.

Accepted Answer

In a body-centered cubic lattice, there are atoms at each corner of the cube (eight atoms) and one atom in the center of the cube, making a total of 2 atoms per unit cell. Therefore, the answer is B, which represents two atoms per unit cell.

Question 2

Which one of the following crystallizes in a metallic lattice?

Accepted Answer

Metallic lattice is a type of crystal structure in which the atoms are held together by metallic bonds. Among the given options, only an element such as potassium (K) can form a metallic lattice.

Question 3

Vanadium crystallizes in a body-centered cubic lattice, and the length of the edge of a unit cell is 305 pm. What is the density of V?

Accepted Answer

To solve this problem, we need to use the formula:

density = (mass of unit cell) / (volume of unit cell)

First, we need to calculate the mass of the unit cell. To do this, we need to know the atomic weight of vanadium, which is 50.9415 g/mol. A body-centered cubic unit cell of vanadium contains 2 atoms, so the mass of the unit cell is:

mass = 2 x atomic weight
mass = 2 x 50.9415 g/mol
mass = 101.883 g

Next, we need to calculate the volume of the unit cell. Since vanadium crystallizes in a body-centered cubic lattice, the volume of the unit cell can be calculated using the formula:

volume = a^3 x (4/3) x pi

where a is the length of the edge of the unit cell.

In this case, a = 305 pm = 305 x 10^-12 m. Plugging in the values, we get:

volume = (305 x 10^-12 m)^3 x (4/3) x pi 
volume = 1.423 x 10^-26 m^3

Now we can plug the mass and volume values into the density formula:

density = mass / volume 
density = 101.883 g / 1.423 x 10^-26 m^3 
density = 5.96 x 10^3 kg/m^3

To convert this to g/cm3, we divide by 1000:

density = 5.96 x 10^3 / 1000 g/cm3 
density = 5.96 g/cm3

Therefore, the answer is C (5.96 g/cm3).

Question 4

One of the crystalline forms of zinc oxide is a structure where the oxygen atoms are at the lattice points in a face-centered cubic lattice. How many atoms are in each unit cell?

Accepted Answer

The answer of One of the crystalline forms of zinc...

Question 5

What is the energy in kJ/mol required to melt 1 mole of a solid?

Accepted Answer

The energy required to melt one mole of a solid is known as the molar heat of fusion. It is the amount of energy required to change a solid into a liquid at its melting point. The units of molar heat of fusion are kJ/mol. Therefore, the best choice is D - molar heat of fusion.

Question 6

The zincblende structure of ZnS has the relatively large sulfide ions arranged at the lattice points of a face-centered cubic structure. The edge length of this cubic unit cell is 540.9 pm. Determine the density of zincblende.

Accepted Answer

The density of zincblende can be calculated using the formula $\rho = \frac{Z \times M}{a^3 \times N_A}$, where $\rho$ is the density, $Z$ is the number of formula units per unit cell (which is 4 for zincblende), $M$ is the molar mass of ZnS (approximately 97.46 g/mol), $a$ is the edge length of the cubic unit cell converted to cm (540.9 pm = 5.409 x 10^-8 cm), and $N_A$ is Avogadro's number (6.022 x 10^23 mol^-1). Plugging in the values, the calculation yields a density close to 4.09 g/cm^3, making option D correct.

Question 7

Iron crystallizes in the body-centered cubic lattice. What is the coordination number for Fe?

Accepted Answer

In a body-centered cubic lattice, each atom located at the center of the cube is coordinated to eight atoms situated at the vertices of the cube. Therefore, the coordination number for Fe in a body-centered cubic lattice is 8. In a body-centered cubic lattice, each atom is surrounded by 8 neighboring atoms. Therefore, the coordination number for iron in a body-centered cubic lattice is 8.

Question 8

What mass of water would need to evaporate from your skin in order to dissipate 1.70 ×10⁵ J of heat from the surface of your body? H₂O(l) → H₂O(g) ΔH_vap = 40.7 kJ/mol

Accepted Answer

First, we need to convert the heat dissipated from the body from joules to kilojoules:
1.70 ×10^15 J ÷ 1000 = 1.70 ×10^12 kJ

Next, we can use the given molar heat of vaporization of water to calculate the amount of water that needs to evaporate:
40.7 kJ/mol × x mol = 1.70 ×10^12 kJ
x = 4.18 × 10^10 mol

Finally, we can convert moles of water to grams of water using the molar mass of water:
4.18 × 10^10 mol × 18.015 g/mol = 7.52 × 10^11 g
or
75.2 g

Therefore, the mass of water that needs to evaporate from the skin is approximately 75.2 g. Option C is the correct choice.

Question 9

Which of the following lacks a regular three-dimensional arrangement of atoms?

Accepted Answer

Amorphous solids do not have a regular three-dimensional arrangement of atoms. Unlike crystalline solids, their atoms or molecules are arranged in a random or disordered manner. Ionic crystals, molecular solids, and some types of solids may have a regular arrangement of atoms. Simply saying "solid" is too general and could refer to any type of solid.

Question 10

Which one of the following substances crystallizes as a molecular solid?

Accepted Answer

Out of the given options, only CH₃OH is a molecular compound containing discrete molecules held together by intermolecular forces. The other options are either ionic (KI, Sn) or network covalent (SiO₂, Al₂(SO₄)₃), which do not have individual molecules. CH3OH, or methanol, is a molecular compound, meaning it is composed of discrete covalently bonded molecules. When solidified, these molecules pack together tightly to form a molecular solid. The other answer choices are either ionic compounds (KI), network covalent solids (SiO2 and Al12(SiO4)13), or metals (Sn).

Question 11

For the solid forms of the following elements, which one is most likely to be of the molecular type?

Accepted Answer

Sulfur (S) is most likely to be of the molecular type in its solid form, existing as S8 molecules, unlike the others which are metallic (Cs, Pb, Cr) or network covalent solids (C as diamond or graphite).

Question 12

Which one of the following substances does not exist in the indicated solid type?

Accepted Answer

SiO₂ is not a known substance and thus cannot exist in any solid type.

Question 13

Which is the correct equation for the molar heat of sublimation?

Accepted Answer

The correct equation for the molar heat of sublimation (ΔH_sub) is the sum of the molar heat of fusion (ΔH_fus) and the molar heat of vaporization (ΔH_vap). This is because sublimation involves a solid turning directly into a gas, effectively undergoing both fusion (solid to liquid) and vaporization (liquid to gas) in one step.

Question 14

The number of atoms in a face-centered cubic unit cell is

Accepted Answer

In a face-centered cubic (FCC) unit cell, there are 8 corner atoms each contributing 1/8th of an atom to the unit cell, and 6 face-centered atoms each contributing 1/2 of an atom. This totals to 4 atoms per unit cell (8*(1/8) + 6*(1/2) = 4).

Question 15

Lead crystallizes in the face-centered cubic lattice. What is the coordination number for Pb?

Accepted Answer

In a face-centered cubic (FCC) lattice, each atom is surrounded by 12 others, so the coordination number is 12.

Question 16

What quantity of heat is required to melt 2.00 kg of iron at its melting point (1809 K)? For iron, ΔH_fus = 13.80 kJ/mol.

Accepted Answer

To calculate the heat required to melt iron, we use the following formula:

q = n*ΔHfus

Where:
q = heat required
n = number of moles of iron
ΔHfus = molar enthalpy of fusion

First, we need to calculate the number of moles of iron:

n = mass/molar mass
n = 2.00 kg / (55.85 g/mol)
n = 35.8 mol

Now we can use the formula to calculate q:

q = n*ΔHfus
q = 35.8 mol * 13.80 kJ/mol
q = 494 kJ

Therefore, the heat required to melt 2.00 kg of iron is 494 kJ. The correct answer is (D).

Question 17

Platinum has a face-centered cubic crystal structure and a density of 21.5 g/cm³. What is the radius of a platinum atom?

Accepted Answer

The face-centered cubic (FCC) structure has 4 atoms per unit cell. Using the density formula and the volume of the unit cell, the atomic radius can be calculated. For platinum, this results in a radius of approximately 139 pm.

Question 18

If liquid bromine is cooled to form a solid, which type of solid does it form?

Accepted Answer

Bromine is a nonmetal and exists as a diatomic molecule (Br2) in its liquid and solid states. Therefore, it forms a molecular solid when cooled to a solid state.

Question 19

Palladium crystallizes in a face-centered cubic unit cell. Its density is 12.0 g/cm³ at 27°C. What is the atomic radius of Pd?

Accepted Answer

The answer of Palladium crystallizes in a face-centered cubic unit...

Question 20

The atomic planes in a graphite crystal are separated by 335 pm. At what angle would you find the first-order (n = 1) diffraction of 0.154-nm X rays from a graphite crystal?

Accepted Answer

The answer of The atomic planes in a graphite crystal...

Quiz 11: Intermolecular Forces and the Physical Properties of Liquids and Solids

A metal such as chromium in the body-centered cubic lattice has ________ atom(s) per unit cell.

Which one of the following crystallizes in a metallic lattice?

Vanadium crystallizes in a body-centered cubic lattice, and the length of the edge of a unit cell is 305 pm. What is the density of V?

One of the crystalline forms of zinc oxide is a structure where the oxygen atoms are at the lattice points in a face-centered cubic lattice. How many atoms are in each unit cell?

What is the energy in kJ/mol required to melt 1 mole of a solid?

The zincblende structure of ZnS has the relatively large sulfide ions arranged at the lattice points of a face-centered cubic structure. The edge length of this cubic unit cell is 540.9 pm. Determine the density of zincblende.

Iron crystallizes in the body-centered cubic lattice. What is the coordination number for Fe?

What mass of water would need to evaporate from your skin in order to dissipate 1.70 ×10⁵ J of heat from the surface of your body? H₂O(l) → H₂O(g) ΔH_vap = 40.7 kJ/mol

Which of the following lacks a regular three-dimensional arrangement of atoms?

Which one of the following substances crystallizes as a molecular solid?

For the solid forms of the following elements, which one is most likely to be of the molecular type?

Which one of the following substances does not exist in the indicated solid type?

Which is the correct equation for the molar heat of sublimation?

The number of atoms in a face-centered cubic unit cell is

Lead crystallizes in the face-centered cubic lattice. What is the coordination number for Pb?

What quantity of heat is required to melt 2.00 kg of iron at its melting point (1809 K) ? For iron, ΔH_fus = 13.80 kJ/mol.

Platinum has a face-centered cubic crystal structure and a density of 21.5 g/cm³. What is the radius of a platinum atom?

If liquid bromine is cooled to form a solid, which type of solid does it form?

Palladium crystallizes in a face-centered cubic unit cell. Its density is 12.0 g/cm³ at 27°C. What is the atomic radius of Pd?

The atomic planes in a graphite crystal are separated by 335 pm. At what angle would you find the first-order (n = 1) diffraction of 0.154-nm X rays from a graphite crystal?

Quiz 11: Intermolecular Forces and the Physical Properties of Liquids and Solids

A metal such as chromium in the body-centered cubic lattice has ________ atom(s) per unit cell.

Which one of the following crystallizes in a metallic lattice?

Vanadium crystallizes in a body-centered cubic lattice, and the length of the edge of a unit cell is 305 pm. What is the density of V?

One of the crystalline forms of zinc oxide is a structure where the oxygen atoms are at the lattice points in a face-centered cubic lattice. How many atoms are in each unit cell?

What is the energy in kJ/mol required to melt 1 mole of a solid?

The zincblende structure of ZnS has the relatively large sulfide ions arranged at the lattice points of a face-centered cubic structure. The edge length of this cubic unit cell is 540.9 pm. Determine the density of zincblende.

Iron crystallizes in the body-centered cubic lattice. What is the coordination number for Fe?

What mass of water would need to evaporate from your skin in order to dissipate 1.70 ×105 J of heat from the surface of your body? H2O(l) → H2O(g) ΔHvap = 40.7 kJ/mol

Which of the following lacks a regular three-dimensional arrangement of atoms?

Which one of the following substances crystallizes as a molecular solid?

For the solid forms of the following elements, which one is most likely to be of the molecular type?

Which one of the following substances does not exist in the indicated solid type?

Which is the correct equation for the molar heat of sublimation?

The number of atoms in a face-centered cubic unit cell is

Lead crystallizes in the face-centered cubic lattice. What is the coordination number for Pb?

What quantity of heat is required to melt 2.00 kg of iron at its melting point (1809 K) ? For iron, ΔHfus = 13.80 kJ/mol.

Platinum has a face-centered cubic crystal structure and a density of 21.5 g/cm3. What is the radius of a platinum atom?

If liquid bromine is cooled to form a solid, which type of solid does it form?

Palladium crystallizes in a face-centered cubic unit cell. Its density is 12.0 g/cm3 at 27°C. What is the atomic radius of Pd?

The atomic planes in a graphite crystal are separated by 335 pm. At what angle would you find the first-order (n = 1) diffraction of 0.154-nm X rays from a graphite crystal?

What mass of water would need to evaporate from your skin in order to dissipate 1.70 ×10⁵ J of heat from the surface of your body? H₂O(l) → H₂O(g) ΔH_vap = 40.7 kJ/mol

What quantity of heat is required to melt 2.00 kg of iron at its melting point (1809 K) ? For iron, ΔH_fus = 13.80 kJ/mol.

Platinum has a face-centered cubic crystal structure and a density of 21.5 g/cm³. What is the radius of a platinum atom?

Palladium crystallizes in a face-centered cubic unit cell. Its density is 12.0 g/cm³ at 27°C. What is the atomic radius of Pd?