Question 1

The heat of fusion for napthalene (C₁₀H₈) is 18.98 kJ/mol and for sodium is 2.60 kJ/mol. The amount of heat that would melt 37.0 grams of napthalene would melt how many grams of sodium?

Accepted Answer

First, we need to use the heat of fusion of napthalene to determine how much heat is required to melt 37.0 grams:

Heat required = (18.98 kJ/mol) × (37.0 g) / (128.17 g/mol) = 5.48 kJ

Next, we can use the amount of heat required to melt 37.0 grams of sodium:

(5.48 kJ) / (2.60 kJ/mol) × (22.99 g/mol) = 48.4 g

Therefore, the answer is D: 48.4 g of sodium.

Question 2

All sides are equal in length and all angles are right angles. There is an atom at each corner and one at the center of each side. This is a ________.

Accepted Answer

The given description matches that of a face-centered cubic cell, which has atoms at each corner and one at the center of each face.

Question 3

Which of the following compounds has the largest lattice energy? MgCO₃, Na₂CO₃, Al₂(CO₃)₂

Accepted Answer

The answer of Which of the following compounds has the...

Question 4

The heat of fusion for water is 6.01 kJ/mol and for ethyl alcohol is 5.01 kJ/mol. The amount of heat that would melt 25.0 grams of water would melt how many grams of ethyl alcohol?

Accepted Answer

First, calculate the moles of water in 25.0 grams (molar mass of water = 18.015 g/mol), which gives approximately 1.387 moles. The heat required to melt this amount of water is 1.387 moles * 6.01 kJ/mol = 8.33 kJ. To find the mass of ethyl alcohol that can be melted with the same amount of heat, divide the total heat by the heat of fusion for ethyl alcohol (5.01 kJ/mol) to get the moles of ethyl alcohol, then multiply by its molar mass (46.07 g/mol) to get the mass in grams. This calculation yields approximately 76.7 grams.

Question 5

Ethyl alcohol (CH₃CH₂OH) has a heat of fusion of 5.01 kJ/mol. How much heat in kJ is required to melt 137g of ethyl alcohol?

Accepted Answer

To find the heat required, first calculate the moles of ethyl alcohol: 137 g / 46.08 g/mol = 2.973 moles. Then multiply by the heat of fusion: 2.973 moles × 5.01 kJ/mol = 14.9 kJ.

Question 6

Given the following information, calculate ΔH°(in kcal mol-1) for: 
I(g) + e- → I-(g)

Accepted Answer

The answer of Given the following information, calculate ΔH°(in kcal...

Question 7

All sides are equal in length and all angles are right angles. There is an atom at each corner and one in the absolute center. This is a ________.

Accepted Answer

The description matches that of a body-centered cubic cell.

Question 8

The triple point of H₂O is at 4.58 mmHg and +0.01°C. Some H₂O at -50°C is heated to 120°C at a constant pressure of 0.5 atm. The changes of state occurring in this process are:

Accepted Answer

At the initial temperature of -50°C, H₂O is in the solid state. Heating it to 120°C at a constant pressure of 0.5 atm, first the solid will change to liquid as the temperature reaches the melting point. Then, as the temperature continues to increase, the liquid will change to gas as it reaches the boiling point. Therefore, the changes of state occurring in this process are solid to liquid to gas, which corresponds to choice B.

Question 9

List the following ionic compounds in order of increasing solubility in water: RbI, CaO, KCl

Accepted Answer

This is because CaO is not very soluble in water (it is a basic oxide and reacts with water to form Ca(OH)2), whereas KCl and RbI are both highly soluble in water due to their ionic nature. Therefore, the order of increasing solubility would be CaO < KCl = RbI, making choice D the best answer.

Question 10

Given the following information, calculate ΔH°(in kcal mol-1) for: CaI₂(s) → Ca⁺²(g) +2 I-(g)

Accepted Answer

To calculate ΔH°, we need to use the enthalpies of formation of the products and reactants. ΔH° = ΣnΔH°(products) - ΣnΔH°(reactants) We can use the following values: ΔH°f(CaI₂) = 0 kcal mol-1 (given) ΔH°f(Ca⁺²) = -118 kcal mol-1 (from a table of thermodynamic values) ΔH°f(I-) = 0 kcal mol-1 (I2(s) is the reference state for halogens, and has a ΔH°f of 0 kcal mol-1) ΔH°f(⁺²) = 104 kcal mol-1 (from a table of thermodynamic values) ΔH° = (1*(-118) + 2*104 + 0) - (1*0 + 12*0 + 1*0) ΔH° = 128 kcal mol-1 The answer closest to this value is E: 1288 kcal mol^-1.

Question 11

The process in which a gas is transformed into a solid is called ________.

Accepted Answer

The process in which a gas is directly transformed into a solid without passing through the liquid state is called deposition. This can occur when the temperature of the gas is lowered below its sublimation point. Options A, B, C and E represent the processes of transforming a substance from one state to another, but do not specifically refer to the transformation of a gas into a solid.

Question 12

If a substance has a heat of condensation of -1.46 kJ/g and a heat of sublimation of 4.60 kJ/g, what is its heat of solidification in kJ/g?

Accepted Answer

The answer of If a substance has a heat of...

Question 13

Given the following information, calculate ΔH°(in kcal mol-1) for: Cl(g) + e- → Cl-(g) Process ΔH° (kcal mol-1) Li(s) → Li(g) +37 Li(g) → Li+(g) + e- +124 Cl₂(g) → 2Cl(g) +58 (per mole Cl₂) LiCl(s) → Li⁺(g) + Cl-(g) +216 2Li(s) + Cl₂(g) → 2LiCl(s) -109 (per mole LiCl)

Accepted Answer

The answer of Given the following information, calculate ΔH°(in kcal...

Question 14

A crystal does not conduct electricity, yet its melt and aqueous solutions do. It is hard and brittle and melts at a high temperature. What type of crystal is it?

Accepted Answer

The properties described fit those of an ionic crystal. Ions in the crystal lattice are held together by strong electrostatic forces and do not conduct electricity in the solid state because the ions are fixed in place. However, when melted or dissolved in water, the ions are free to move and conduct electricity.

Question 15

Given the following information, calculate ΔH°(in kcal mol-1) for: LiCl(s) → Cl-(g) + Li+(g) Process ΔH° (kcal mol-1) Li(s) → Li(g) +37 Li(g) → Li⁺(g) + e- +124 Cl₂(g) → 2Cl(g) +29 (per mole Cl) Cl(g) + e- → Cl-(g) -83 2Li(s) + Cl₂(g) → 2LiCl(s) -109 (per mole LiCl)

Accepted Answer

The answer of Given the following information, calculate ΔH°(in kcal...

Question 16

Given the following information, calculate ΔH°(in kcal mol-1) for: I(g) + e- → I-(g)

Accepted Answer

The ΔH° for the reaction can be calculated using the equation: ΔH° = ΔH°(I-) - ΔH°(I) - ΔH°(e-)
From standard enthalpy of formation data, ΔH°(I-) = -71 kcal mol-1 and ΔH°(I) = 0 kcal mol-1. The ΔH° for an electron is typically taken to be -1 kcal mol-1. Therefore, ΔH° = -71 - 0 - (-1) = -70 kcal mol-1. The closest answer choice to this value is C, which is -71 kcal mol-1.

Question 17

If 34 g of a solid of mol mass = 174 g/mol requires 21.3 kJ to melt it, what is the molar heat of fusion in kJ/mol?

Accepted Answer

The molar heat of fusion is calculated by dividing the energy required to melt the solid by the number of moles of the solid. The number of moles is given by the mass of the solid divided by its molar mass. Therefore, the molar heat of fusion is (21.3 kJ) / (34 g / 174 g/mol) = (21.3)(174/34) kJ/mol.

Question 18

Given the following information, calculate ΔH°(in kcal mol^-1) for: NaI(s) → Na+(g) + I-(g)

Accepted Answer

The answer of Given the following information, calculate ΔH°(in kcal...

Question 19

An arrangement in which every other layer is identical (ABABABAB) is ________.

Accepted Answer

The arrangement described is a hexagonal close packed (HCP) structure, with every other layer being identical and stacked on top of each other in an ABABABAB pattern. Option A (octahedral holes) and B (tetrahedral holes) refer to the void spaces within close-packed structures and are not relevant to the given arrangement. Options D and E (cubic close packing and face centered cubic) describe different types of close-packed crystal structures that do not have the alternating layer pattern described in the question.

Question 20

A crystal does not conduct electricity, even after melting. It is hard and brittle and melts at a very high temperature. What type of crystal is it?

Accepted Answer

Covalent network crystals are made up of atoms that are covalently bonded to each other in a continuous network, such as diamond or silica. These types of crystals do not have any free electrons or ions to conduct electricity, even when melted. They also have high melting points and are typically hard and brittle.

Quiz 12: Intermolecular Forces: Liquids and Solids

The heat of fusion for napthalene (C₁₀H₈) is 18.98 kJ/mol and for sodium is 2.60 kJ/mol. The amount of heat that would melt 37.0 grams of napthalene would melt how many grams of sodium?

All sides are equal in length and all angles are right angles. There is an atom at each corner and one at the center of each side. This is a ________.

Which of the following compounds has the largest lattice energy? MgCO₃, Na₂CO₃, Al₂(CO₃) ₂

The heat of fusion for water is 6.01 kJ/mol and for ethyl alcohol is 5.01 kJ/mol. The amount of heat that would melt 25.0 grams of water would melt how many grams of ethyl alcohol?

Ethyl alcohol (CH₃CH₂OH) has a heat of fusion of 5.01 kJ/mol. How much heat in kJ is required to melt 137g of ethyl alcohol?

Given the following information, calculate ΔH°(in kcal mol-1) for: I(g) + e- → I-(g)

All sides are equal in length and all angles are right angles. There is an atom at each corner and one in the absolute center. This is a ________.

The triple point of H₂O is at 4.58 mmHg and +0.01°C. Some H₂O at -50°C is heated to 120°C at a constant pressure of 0.5 atm. The changes of state occurring in this process are:

List the following ionic compounds in order of increasing solubility in water: RbI, CaO, KCl

Given the following information, calculate ΔH°(in kcal mol-1) for: CaI₂(s) → Ca⁺²(g) +2 I-(g)

The process in which a gas is transformed into a solid is called ________.

If a substance has a heat of condensation of -1.46 kJ/g and a heat of sublimation of 4.60 kJ/g, what is its heat of solidification in kJ/g?

Given the following information, calculate ΔH°(in kcal mol-1) for: Cl(g) + e- → Cl-(g) Process ΔH° (kcal mol-1) Li(s) → Li(g) +37 Li(g) → Li+(g) + e- +124 Cl₂(g) → 2Cl(g) +58 (per mole Cl₂) LiCl(s) → Li⁺(g) + Cl-(g) +216 2Li(s) + Cl₂(g) → 2LiCl(s) -109 (per mole LiCl)

A crystal does not conduct electricity, yet its melt and aqueous solutions do. It is hard and brittle and melts at a high temperature. What type of crystal is it?

Given the following information, calculate ΔH°(in kcal mol-1) for: LiCl(s) → Cl-(g) + Li+(g) Process ΔH° (kcal mol-1) Li(s) → Li(g) +37 Li(g) → Li⁺(g) + e- +124 Cl₂(g) → 2Cl(g) +29 (per mole Cl) Cl(g) + e- → Cl-(g) -83 2Li(s) + Cl₂(g) → 2LiCl(s) -109 (per mole LiCl)

Given the following information, calculate ΔH°(in kcal mol-1) for: I(g) + e- → I-(g)

If 34 g of a solid of mol mass = 174 g/mol requires 21.3 kJ to melt it, what is the molar heat of fusion in kJ/mol?

Given the following information, calculate ΔH°(in kcal mol^-1) for: NaI(s) → Na+(g) + I-(g)

An arrangement in which every other layer is identical (ABABABAB) is ________.

A crystal does not conduct electricity, even after melting. It is hard and brittle and melts at a very high temperature. What type of crystal is it?

Quiz 12: Intermolecular Forces: Liquids and Solids

The heat of fusion for napthalene (C10H8) is 18.98 kJ/mol and for sodium is 2.60 kJ/mol. The amount of heat that would melt 37.0 grams of napthalene would melt how many grams of sodium?

All sides are equal in length and all angles are right angles. There is an atom at each corner and one at the center of each side. This is a ________.

Which of the following compounds has the largest lattice energy? MgCO3, Na2CO3, Al2(CO3) 2

The heat of fusion for water is 6.01 kJ/mol and for ethyl alcohol is 5.01 kJ/mol. The amount of heat that would melt 25.0 grams of water would melt how many grams of ethyl alcohol?

Ethyl alcohol (CH3CH2OH) has a heat of fusion of 5.01 kJ/mol. How much heat in kJ is required to melt 137g of ethyl alcohol?

Given the following information, calculate ΔH°(in kcal mol-1) for: I(g) + e- → I-(g)

All sides are equal in length and all angles are right angles. There is an atom at each corner and one in the absolute center. This is a ________.

The triple point of H2O is at 4.58 mmHg and +0.01°C. Some H2O at -50°C is heated to 120°C at a constant pressure of 0.5 atm. The changes of state occurring in this process are:

List the following ionic compounds in order of increasing solubility in water: RbI, CaO, KCl

Given the following information, calculate ΔH°(in kcal mol-1) for: CaI2(s) → Ca+2(g) +2 I-(g)

The process in which a gas is transformed into a solid is called ________.

If a substance has a heat of condensation of -1.46 kJ/g and a heat of sublimation of 4.60 kJ/g, what is its heat of solidification in kJ/g?

Given the following information, calculate ΔH°(in kcal mol-1) for: Cl(g) + e- → Cl-(g) Process ΔH° (kcal mol-1) Li(s) → Li(g) +37 Li(g) → Li+(g) + e- +124 Cl2(g) → 2Cl(g) +58 (per mole Cl2) LiCl(s) → Li+(g) + Cl-(g) +216 2Li(s) + Cl2(g) → 2LiCl(s) -109 (per mole LiCl)

A crystal does not conduct electricity, yet its melt and aqueous solutions do. It is hard and brittle and melts at a high temperature. What type of crystal is it?

Given the following information, calculate ΔH°(in kcal mol-1) for: LiCl(s) → Cl-(g) + Li+(g) Process ΔH° (kcal mol-1) Li(s) → Li(g) +37 Li(g) → Li+(g) + e- +124 Cl2(g) → 2Cl(g) +29 (per mole Cl) Cl(g) + e- → Cl-(g) -83 2Li(s) + Cl2(g) → 2LiCl(s) -109 (per mole LiCl)

Given the following information, calculate ΔH°(in kcal mol-1) for: I(g) + e- → I-(g)

If 34 g of a solid of mol mass = 174 g/mol requires 21.3 kJ to melt it, what is the molar heat of fusion in kJ/mol?

Given the following information, calculate ΔH°(in kcal mol-1) for: NaI(s) → Na+(g) + I-(g)

An arrangement in which every other layer is identical (ABABABAB) is ________.

A crystal does not conduct electricity, even after melting. It is hard and brittle and melts at a very high temperature. What type of crystal is it?

The heat of fusion for napthalene (C₁₀H₈) is 18.98 kJ/mol and for sodium is 2.60 kJ/mol. The amount of heat that would melt 37.0 grams of napthalene would melt how many grams of sodium?

Which of the following compounds has the largest lattice energy? MgCO₃, Na₂CO₃, Al₂(CO₃) ₂

Ethyl alcohol (CH₃CH₂OH) has a heat of fusion of 5.01 kJ/mol. How much heat in kJ is required to melt 137g of ethyl alcohol?

The triple point of H₂O is at 4.58 mmHg and +0.01°C. Some H₂O at -50°C is heated to 120°C at a constant pressure of 0.5 atm. The changes of state occurring in this process are:

Given the following information, calculate ΔH°(in kcal mol-1) for: CaI₂(s) → Ca⁺²(g) +2 I-(g)

Given the following information, calculate ΔH°(in kcal mol-1) for: Cl(g) + e- → Cl-(g) Process ΔH° (kcal mol-1) Li(s) → Li(g) +37 Li(g) → Li+(g) + e- +124 Cl₂(g) → 2Cl(g) +58 (per mole Cl₂) LiCl(s) → Li⁺(g) + Cl-(g) +216 2Li(s) + Cl₂(g) → 2LiCl(s) -109 (per mole LiCl)

Given the following information, calculate ΔH°(in kcal mol-1) for: LiCl(s) → Cl-(g) + Li+(g) Process ΔH° (kcal mol-1) Li(s) → Li(g) +37 Li(g) → Li⁺(g) + e- +124 Cl₂(g) → 2Cl(g) +29 (per mole Cl) Cl(g) + e- → Cl-(g) -83 2Li(s) + Cl₂(g) → 2LiCl(s) -109 (per mole LiCl)

Given the following information, calculate ΔH°(in kcal mol^-1) for: NaI(s) → Na+(g) + I-(g)