Chemistry - Study Guide

Stoichiometry, Emission Spectra, literally everything from Gr 11 Chemistry

How many moles of FeS2 are required to produce 32 g of SO2? (Ar: S \= 32, O \= 16)

4FeS2 (s) + 11O2 (g) → 2Fe2O3 (s) + 8SO2 (g)

0.25

The volume of a sample of gas measured at 27 °C is 10.0 dm3. What is the temperature when the volume is reduced to 9.0 dm3 at the same pressure?

24.3 °C

16 g of bromine react with 5.2 g of metal, M, to form MBr2. What is the relative atomic mass of the metal M? (Ar : Br \= 80)

52

An antacid tablet containing 0.50 g of NaHCO3 (Mr \= 84) is dissolved in water to give a volume of 250 cm3. What is the concentration, in mol dm−3, of HCO3− in this solution?

0.50/(85*0.250)

Which is a homogeneous mixture?

Ethanol and Water

What is the molecular formula of a hydrocarbon containing 84.6% carbon by mass with a molar mass of 142.3 g mol−1?

C10H22

Which graph shows the relationship between the volume and pressure of a fixed mass of an ideal gas?

Decreasing Curve

What is the percentage yield when 7 g of ethene produces 6 g of ethanol?
Mr(ethene) \= 28 and Mr(ethanol) \= 46
C2H4(g) + H2O(g) → C2H5OH(g)

6*28*100/7*46

What is the sum of the coefficients when the equation is balanced with the lowest whole number ratio?

__Na2S2O3(aq) + __HCl(aq) → __S(s) + __SO2(g) + __NaCl(aq) + __H2O(l)

8

What is the number of atoms of oxygen in 2.0 mol of hydrated sodium carbonate, Na2CO3•10H2O? Avogadro's constant, L or NA: 6.02 × 1023 mol-1

1.6 × 10^25

Which statements are correct for the emission spectrum of hydrogen?

I. The lines converge at higher frequencies

II. Electron transitions to n \= 2 are responsible for lines in the visible region.

III. Lines are produced when electrons move from lower to higher energy levels.

I and II only

Which statement about ^56Fe3+ and ^54Fe2+ is correct?

Both have the same number of protons.

Which shows the number of subatomic particles in 31P3−?

15 Protons: 16 Neutrons: 18 Electrons

Which are correct statements about the emission spectrum of hydrogen in the visible region?

I. The red line has a lower energy than the blue line.

II. The lines converge at longer wavelength.

III. The frequency of the blue line is greater than the frequency of the red line.

I and III only

What is the composition of the nucleus of 26Mg?

12 Protons: 14 Neutrons: 12 Electrons

What is the number of protons and the number of neutrons in 131I?

53 Protons: 78 Neutrons

Which is the electron configuration of a chromium atom in the ground state?

\[Ar]4s1 3d5

In which set do all the species contain more electrons than neutrons?

14N3-, 16O2-, 11C

Which electron transition in the hydrogen atom emission spectrum emits radiation with the longest wavelength?

n \= 3 → n \= 2

The full electron configuration of an element is:
1s2 2s2 2p6 3s2 3p2
To which group and period does the element belong?

Group 14 Period 3

The values for the first three successive ionization energies for two elements X and Z are given.

Which pair of elements represents X and Z?

X\=Li Z\=C

Which transition on the diagram corresponds to the ionization of hydrogen in the ground state?

Longest Line, A

The graph shows the first ionization energies of some consecutive elements.

X is in group 18

The graph represents the first ten ionisation energies (IE) of an element.

What is the element?

O

Which statement explains one of the decreases in first ionization energy (I.E.) across period 3?

The electron-electron repulsion is greater, for the electron with the opposite spin, in element S than in element P.

The diagram shows the first ionization energies of four consecutive elements in the periodic table. Which element is in Group 14?

Second Dot, B

A period 3 element, M, forms an oxide of the type M2O. Which represents the first four successive ionization energies of M?

496-First 4563-Second 6913-Third 9544-Fourth

The first ionization energies (in ) of five successive elements in the periodic table are:

1314, 1681, 2081, 496 and 738

What could these elements be?

The last three elements of one period and the first two elements of the next period

What is the electron configuration of the copper(I) ion, Cu+ ?

1s2 2s2 2p6 3s2 3p6 4s1 3d10

Successive ionization energies for an element, Z, are shown in the table below.

What is the most likely formula for the ion of Z?

Z2+

Which oxides produce an acidic solution when added to water?

I. Al2O3 and SiO2

II. P4O6 and P4O10

III. NO2 and SO2

II and III only

Which species will require the least energy for the removal of one electron?

Al2+

Which describes the oxide of sodium, Na2O?

Bonding-Ionic
Conduction of Electricity-As A Liquid Only
ph of Aqueous Solution-High

Which statement is correct?

First ionization energy decreases down group 1.

Which increase across a period from left to right?

1st Ionization Energy
Electronegativity

Which element is in the p-block?

Pb

Which trends are correct across period 3 (from Na to Cl)?

I. Atomic radius decreases

II. Melting point increases

III. First ionization energy increases

I and III only

Which oxide dissolves in water to give a solution with a pH below 7?

MgO

Which oxide, when added to water, produces the solution with the highest pH?

Na2O

Which metal has the strongest metallic bond?

Rb

Which is correct for the complex ion in [Fe(H2O)5Cl]SO4?

Oxidation State of Iron\= +3
Overall Charge of the Complex Ion\= 2+

Which complex has the greatest d orbital splitting?

Complex-[Fe(H20)6]3+
Oxidation State of Metal- +3
Color of Complex-Orange

Part of the spectrochemical series is shown for transition metal complexes.

I−< Cl− < H2O < NH3

Which statement can be correctly deduced from the series?

H2O increases the d-d separation more than Cl−.

\[CoCl6]3- is orange while [Co(NH3)6]3+ is yellow. Which statement is correct?

The different ligands cause different splitting in the 3d orbitals.

What is the charge on the iron(III) complex ion in [Fe(OH)2(H2O)4]Br?

1+

Ammonia is a stronger ligand than water. Which is correct when concentrated aqueous ammonia solution is added to dilute aqueous copper(II) sulfate solution?

Ammonia replaces water as a ligand.

What is the correct explanation for the colour of [Cu(H2O)6]2+?

Light is absorbed when an electron moves to a d orbital of higher energy.

Which best explains why transition metal complexes are coloured?

As electrons are promoted to higher energy levels, light of a certain colour is absorbed, and the complementary colour is observed.

The oxidation state of cobalt in the complex ion [Co(NH3)5Br]x is +3. Which of the following statements are correct?

I. The overall charge, x, of the complex ion is 2+
.
II. The complex ion is octahedral.

III. The cobalt(III) ion has a half-filled d-subshell.

I and II only

Which statements are correct about the complex ?

I. Oxidation state of copper is +2.

II. Ammonia is a ligand.

III. Chloride ions act as Lewis acids.

I and II only

How many lone pairs and bonding pairs of electrons surround the central chlorine atom in ClF2+?

Lone Pairs-2
Bonding Pairs-2

Which compound has the highest boiling point?

CH3OCH3

Which molecule is polar?

NCl3

Which species has the same molecular geometry as SO32−?

PF3

Which form of carbon is the poorest electrical conductor?

Diamond

What is the molecular geometry and bond angle in the molecular ion NO3−?

Molecular Geometry- Trigonal Planar
Bond Angle- 120

What are the strongest intermolecular forces between molecules of propanone, CH3COCH3, in the liquid phase?

Dipole-dipole Forces

What is the formula of ammonium phosphate?

(NH4)3PO4

Which species has the longest carbon to oxygen bond length?

CH3OH

What are the predicted electron domain geometries around the carbon and both nitrogen atoms in urea, (NH2)2CO, applying VSEPR theory?

Carbon Atom- Trigonal Planar
Nitrogen Atoms- Trigonal Pyrimidal

What is the number of sigma (σ) and pi (π) bonds in the molecule (NC)2C\=C(CN)2?

A-9
Pi-9

What is the hybridization of the circled carbon, oxygen and nitrogen atoms?

Carbon-sp2
Oxygen-sp3
Nitrogen-sp2

Which molecules have at least one sp2 hybridized atom?

I. CH3COOH

II. CH3COCH3

III. CH2CHCH2OH

I, II and III

Which can be represented with only one Lewis structure?

CH2O

Which molecule has an expanded octet?

SF4

Which overlap of atomic orbitals leads to the formation of only a sigma (σ) bond?

I. s − p

II. p − p

III. s − s

II and III only

What is the hybridization state and electron domain geometry around the circled C, N and O atoms?

C- sp3 and tetrahedral
O- sp2 and trigonal planar
N- sp2 and trigonal planar

Which combination describes the PH4+ ion?

Molecular Geometry- Tetrahedral
Central Atom Hybridization- sp3

Which combination describes the bonding and structure in benzoic acid, C6H5COOH?

\# of electron domains per carbon atom- 3
\# of pi electrons- 8
\# of alpha bonds- 15

Which species have resonance structures?

I. Ozone, O3

II. Carbon dioxide, CO2

III. Benzene, C6H6

I and III only

Consider the following reactions:
Fe2O3 (s) + CO (g) → 2FeO (s) + CO2 (g) ΔHΘ \= −3 kJ
Fe (s) + CO2 (g) → FeO (s) + CO (g) ΔHΘ \= +11 kJ

What is the ΔHΘ value, in kJ, for the following reaction?
Fe2O3 (s) + 3CO (g) → 2Fe (s) + 3CO2 (g)

-25

Which is correct when Ba(OH)2 reacts with NH4Cl?

Ba(OH)2 (s) + 2NH4Cl (s) → BaCl2 (aq) + 2NH3 (g) + 2H2O (l) ΔHΘ \= +164 kJ mol−1

Temperature- Decreases

Enthalpy- Products have higher enthalpy than reactants

Stability- Products are less stable than reactants

Consider the following reaction:
N2 (g) + 3H2 (g) 2NH3 (g)

Which calculation gives ΔHΘ, in kJ, for the forward reaction?

y + 3x − 6z

The enthalpy of combustion of ethanol is determined by heating a known mass of tap water in a glass beaker with a flame of burning ethanol.
Which will lead to the greatest error in the final result?

Assuming all the energy from the combustion will heat the water

What is the enthalpy of combustion of butane in kJ mol−1?
2C4H10(g) + 13O2(g) → 8CO2(g) + 10H2O(l)

8x + 10y − 2z

Which statement is correct?

In an endothermic reversible reaction, the activation energy of the forward reaction is greater than that of the reverse reaction.

Which describes the reaction shown in the potential energy profile?

The reaction is endothermic and the products have greater enthalpy than the reactants.

What is the enthalpy change of combustion of urea, (NH2)2CO, in kJ mol−1?
2(NH2)2CO(s) + 3O2(g) → 2CO2(g) + 2N2(g) + 4H2O(l)

2 × (−394) + 4 × (−286) −2 × (−333)

Two 100 cm3 aqueous solutions, one containing 0.010 mol NaOH and the other 0.010 mol HCl, are at the same temperature.
When the two solutions are mixed the temperature rises by y °C.
Assume the density of the final solution is 1.00 g cm−3.
Specific heat capacity of water \= 4.18 J g−1 K−1
What is the enthalpy change of neutralization in kJ mol−1?

200*4.18*y/1000*0.010

Which statement is correct for this reaction?
Fe2O3 (s) + 3CO (g) → 2Fe (s) + 3CO2 (g) ΔH \= −26.6 kJ

13.3 kJ are released for every mole of Fe produced.

What are the signs of ΔHΘ and ΔSΘ for the reaction, which is spontaneous at low temperature and non-spontaneous at very high temperature?
ΔGΘ \= ΔHΘ − TΔSΘ
SO3 (g) + CaO (s) → CaSO4 (s)

H\= -
S\= -

Which change is exothermic?

1/2 Cl2 (g) → Cl (g)

What is the enthalpy of solution of MgF2(s) in kJ mol−1?
Lattice enthalpy of MgF2(s) \= 2926 kJ mol−1
Hydration enthalpy of Mg2+(g) \= −1963 kJ mol−1
Hydration enthalpy of F−(g) \= −504 kJ mol−1

−2926 − (−1963) − 2(−504)

Which statement is correct?

If ΔS < 0, reaction can be spontaneous if temperature is low enough

Which value represents the lattice enthalpy, in kJ mol−1, of strontium chloride, SrCl2?

- (-829) + 164 + 243 + 550 + 1064 - 698

Which system has the most negative entropy change, ΔS, for the forward reaction?

N2(g) + 3H2(g) \== 2NH3(g)

Which statements are correct for ionic compounds?

I. Lattice energy increases as ionic radii increase.

II. Within the same group, the melting point of salts
tends to decrease as the radius of the cation increases.

III. Solubility in water depends on the relative magnitude of the lattice energy compared to the hydration energy.

I and III only

What is the standard enthalpy of formation, in kJ mol-1, of IF (g)?
IF7 (g) + I2 (s) → IF5 (g) + 2IF (g) ΔH \= -89 kJ
ΔH (IF7) \= -941 kJ mol-1
ΔH (IF5) \= -840 kJ mol-1

-95

The combustion of glucose is exothermic and occurs according to the following equation:
C6H12O6 (s) + 6O2 (g) → 6CO2 (g) + 6H2O (g)
Which is correct for this reaction?

H- Positive
S- Positive
Non-Spontaneous

Which equation represents the lattice enthalpy of magnesium sulfide?

MgS (s) → Mg2+ (g) + S2- (g)

Samples of sodium carbonate powder were reacted with separate samples of excess hydrochloric acid.
Na2CO3 (s) + 2HCl (aq) → CO2 (g) + 2NaCl (aq) + H2O (l)
Reaction I: 1.0 g Na2CO3 (s) added to 0.50 mol dm−3 HCl (aq)
Reaction II: 1.0 g Na2CO3 (s) added to 2.0 mol dm−3 HCl (aq)
What is the same for reactions I and II?

Total mass of CO2 produced

What decreases the activation energy of a reaction?

Adding a catalyst

Which change increases the rate of formation of hydrogen when zinc reacts with excess hydrochloric acid, assuming all other conditions remain the same?
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)

Decreasing the size of the zinc particles while keeping the total mass of zinc the same

Which statements are correct?

I. The activation energy of a reaction is not affected by temperature.

II. A catalyst reduces the enthalpy change of a reaction.

III. Catalysts provide alternative reaction pathways.

I and III only

The potential energy profile for the reversible reaction, X + Y Z is shown.

Which arrow represents the activation energy for the reverse reaction, Z → X + Y, with a catalyst?

Middle Line-- C

Which factors can affect the rate of reaction?

I. Particle size of solid reactant

II. Concentration of reacting solution

III. Pressure of reacting gas

I, II and III

The diagram shows the energy profile for a catalysed and uncatalysed reaction.
Which represents the enthalpy change, ΔH, and the activation energy, Ea, for the catalysed reaction?

H- z
E- x+z

Excess magnesium powder was added to a beaker containing hydrochloric acid, HCl (aq).
The mass of the beaker and its contents was recorded and plotted against time (line I).

Increasing the temperature

Copper catalyses the reaction between zinc and dilute sulfuric acid.
Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g)
Why does copper affect the reaction?

Decreases the activation energy

100 cm3 of 10% hydrogen peroxide solution decomposes at 298 K to form water and oxygen.
H2O2(aq) → H2O(l) + O2(g)
The dotted line graph represents the volume of oxygen produced.

Which graph represents the decomposition of an equal volume of a 20% solution under the same conditions?

Highest Line-- A