Which of the following increases as boiling water changes to steam?

degree of disorder of the system

JAMB UTME - Chemistry - 2022 | Green Bridge CBT

Question 1 Report

Complete dehydrogenation of ethyne yields

benzene

methane

ethane

propane

Answer Details

Read lesson note on Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

Chemistry Of Carbon Compounds (Nigeria Only)

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Question 2 Report

2-methylprop-1-ene is a structural isomer of?

But-1-yne

2-methyl But-1-ene

3-methyl prop-1-yne

But-2-ene

Answer Details

Read lesson note on Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

Chemistry Of Carbon Compounds (Nigeria Only)

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Question 3 Report

There is a large temperature interval between the melting point and the boiling point of metal because:

metals have a very high melting point

metals conduct heat very rapidly

melting does not break the metallic bond but boiling does

the crystal lattice of metal is easily broken

Answer Details

The correct answer is: "melting does not break the metallic bond but boiling does." The metallic bond is the force of attraction between metal atoms, which holds them together to form a solid. When a metal is heated, its temperature increases, and at a certain point, the energy provided by the heat is enough to overcome the metallic bond and cause the metal to melt. However, even in the liquid state, the metallic bond remains intact, which is why metals have a very high melting point. On the other hand, when the temperature is further increased, the energy provided by the heat becomes enough to break the metallic bond, and the metal atoms become completely detached from one another. This results in the metal boiling and turning into a gas. Because the metallic bond is much stronger than other types of intermolecular forces, such as van der Waals forces, it requires a lot of energy to break, resulting in a large temperature interval between the melting point and boiling point of metal.

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Read lesson note on Structure Of The Atom (WAEC)

Water

Structure Of The Atom

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Question 4 Report

The boiling point of water, ethanol, toulene and butan-2-ol are 373.0k, 351.3k, 383.6k and 372.5k respectively, which liquid has the highest vapour pressure at 323.0k

water

toluene

ethanol

butan-2-ol

Answer Details

Read lesson note on Kinetic Theory Of Matter And Gas Laws (JAMB)

Kinetic Theory Of Matter And Gas Laws

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Question 5 Report

The removal of rust from iron by treatment with tetraoxosulphate (vi) acid is based on the

Hydrolysis of the iron

Reaction of acid with base

Oxidation of the rust

Dehydration of the iron

Answer Details

Read lesson note on Acids, Bases And Salts (JAMB)

Acids, Bases And Salts

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Question 6 Report

What is the shape of a molecule of CCl4?

Pyramid

tetrahedral

Trigonal planar

linear

Answer Details

The shape of a molecule of CCl4 is tetrahedral.

Read lesson note on Atomic Structure And Bonding (JAMB)

Atomic Structure And Bonding

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Question 7 Report

A metal which can be used as sacrificial anode for preventing corrosion of length of iron pipe is

copper

magnesium

silver

lead

Answer Details

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 8 Report

A chemical widely used as a fertilizer is?

galena

bauxite

emerald

nitrochalk

Answer Details

The chemical widely used as a fertilizer is nitrochalk. Nitrochalk is a type of fertilizer that contains a mixture of ammonium nitrate and calcium carbonate. Ammonium nitrate provides the necessary nitrogen for plant growth, while calcium carbonate helps to balance the soil's pH level. This combination of nutrients helps to promote healthy plant growth and increase crop yields. Nitrochalk is commonly used in agriculture and gardening to fertilize crops such as corn, wheat, and soybeans, as well as fruits and vegetables.

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Acids, Bases And Salts

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Question 9 Report

On the basis of the electrochemical series, which of these ions will show the greater tendency to be discharged at the cathode in an electrolytic cell

^{2 +}

^{2 +}

^{2 +}

^{2 +}

Answer Details

The electrochemical series is a list of metals and ions arranged in order of their decreasing tendency to lose or gain electrons, and thus, their ability to act as reducing or oxidizing agents. The higher the position of a metal or ion in the electrochemical series, the greater its tendency to lose electrons and undergo oxidation, while the lower its position, the greater its tendency to gain electrons and undergo reduction. In an electrolytic cell, the cathode is the electrode where reduction occurs, meaning that cations (positively charged ions) are attracted and gain electrons to form neutral atoms or molecules. Based on the electrochemical series, the ion with the higher position in the series will have a greater tendency to gain electrons and be discharged at the cathode, while the ion with the lower position will have a lower tendency and may not be discharged at all. Among the given options, the electrochemical series order is: Cu2+ > Sn2+ > Fe2+ > Zn2+ Therefore, Cu2+ has the highest tendency to be discharged at the cathode and undergo reduction, while Zn2+ has the lowest tendency. So, in an electrolytic cell, Cu2+ will be discharged at the cathode, while Zn2+ may not be discharged at all, depending on the conditions of the cell.

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Electrolysis

Redox Reactions

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Question 10 Report

The pollutant usually presents in a city which generates its electricity from coal?

fog

carbon(ii)oxide

smog

sulphur(iv)oxide

Answer Details

The pollutant that is usually present in a city that generates its electricity from coal is sulfur dioxide (SO2), also known as sulfur(iv)oxide. When coal is burned to generate electricity, sulfur compounds in the coal are released into the air as SO2. This gas can react with other pollutants and atmospheric conditions to form smog, which can be harmful to human health and the environment. Therefore, it is important to reduce the use of coal in electricity generation and promote cleaner and more sustainable energy sources to reduce the levels of SO2 and other harmful pollutants in the air.

Read lesson note on Acids, Bases And Salts (Nigeria Only) (WAEC)

Read lesson note on Organic Compounds (JAMB)

Read lesson note on Environmental Pollution (JAMB)

Acids, Bases And Salts (Nigeria Only)

Organic Compounds

Environmental Pollution

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Question 11 Report

Which of the following is stable to heat

NaHCO3

( NH4 )2 SO4

Ag NH3

K2 CO3

Answer Details

Out of the given options, K2CO3 is stable to heat.

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Non-metals And Their Compounds

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Question 12 Report

A sample of gas with an initial volume of 2.5 dm3 is heated and then allowed to expand to 7.5 dm3 at constant at pressure. What is the ratio of the final temperature of the initial absolute temperature?

3:1

1:3

2:5

5:2

Answer Details

According to Charles's Law, the ratio of the initial and final temperatures is equal to the ratio of the initial and final volumes at constant pressure. The ratio of the final volume to the initial volume is: Vf / Vi = 7.5 dm3 / 2.5 dm3 = 3 Therefore, the ratio of the final temperature to the initial temperature is also 3: Tf / Ti = Vf / Vi = 3 So the answer is 3:1.

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Kinetic Theory Of Matter And Gas Laws

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Question 13 Report

Which of the following will act as both oxidizing agents and reducing agents?

H2 S

NH3

Cl2

SO2

Answer Details

The oxidizing and reducing properties of a substance depend on its ability to gain or lose electrons. A substance that can gain electrons acts as an oxidizing agent, while a substance that can lose electrons acts as a reducing agent. Among the given options, both Cl2 (chlorine gas) and SO2 (sulfur dioxide) can act as both oxidizing and reducing agents depending on the reaction conditions. - Cl2 can act as an oxidizing agent when it gains electrons to form Cl- ions, and it can act as a reducing agent when it loses electrons to form Cl+ ions. For example, in the reaction Cl2 + 2KBr → 2KCl + Br2, chlorine gas is acting as an oxidizing agent since it is gaining electrons from bromide ions to form bromine gas. However, in the reaction 2Cl- + Cl2 → 2Cl2-, chlorine gas is acting as a reducing agent since it is losing electrons to form chloride ions. - SO2 can act as an oxidizing agent when it gains electrons to form sulfite ions (SO32-), and it can act as a reducing agent when it loses electrons to form sulfur trioxide (SO3). For example, in the reaction SO2 + 2H2S → 3S + 2H2O, sulfur dioxide is acting as a reducing agent since it is losing electrons to form elemental sulfur. However, in the reaction 2SO32- + O2 → 2SO42-, sulfur dioxide is acting as an oxidizing agent since it is gaining electrons to form sulfate ions. H2S (hydrogen sulfide) and NH3 (ammonia) are not likely to act as both oxidizing and reducing agents under normal conditions. H2S tends to act as a reducing agent by donating electrons to oxidizing agents, while NH3 tends to act as a reducing agent by donating electrons to oxidizing agents or as a base by accepting protons.

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Chemical Bonds (Ghana Only)

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Question 14 Report

Alkanes are used mainly?

in the textile industry

in the hydrogenation of oils

as domestic and industrial fuels

as fine chemicals

Answer Details

Read lesson note on Chemistry, Industry And The Environment (WAEC)

Chemistry, Industry And The Environment

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Question 15 Report

Using the metal activity series, the metal that can liberate hydrogen gas from steam is?

iron

copper

tin

lead

Answer Details

The metal that can liberate hydrogen gas from steam is iron. The metal activity series is a list of metals in order of their reactivity, with the most reactive metals at the top and the least reactive metals at the bottom. When a metal is placed in a solution of steam (water vapor), the metal will react with the steam if it is more reactive than hydrogen. In this case, iron is more reactive than hydrogen, so it can displace hydrogen from the steam to form hydrogen gas. This reaction can be represented by the equation: Fe + H2O (steam) → FeO (iron oxide) + H2 (hydrogen gas) So, when steam is passed over iron, hydrogen gas is liberated and iron oxide is formed.

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Question 16 Report

A certain liquid has a high boiling point. It is viscous, non-toxic, and miscible with water to be hygroscopic; this liquid most likely to be

CH3CH2CH2CH2OH

CH3CH2CHOH3

CH3CH2CH2CH2OH3

CH3OHCHOH2OH

Answer Details

The liquid is most likely to be option number 4: CH3OHCHOH2OH, which is also known as glycerol or glycerin. Glycerol has a high boiling point of 290°C, which is much higher than the boiling points of the other options. It is also a viscous liquid, which means it is thick and sticky. Glycerol is non-toxic, and it is often used in food, pharmaceuticals, and cosmetics. Furthermore, glycerol is miscible with water, which means that it can be easily mixed with water to form a homogeneous solution. It is also hygroscopic, which means that it can absorb water from the air. These properties make glycerol a useful substance in many applications, such as as a moisturizer in skincare products or as a humectant in food processing.

Read lesson note on Acids, Bases And Salts (JAMB)

Acids, Bases And Salts

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Question 17 Report

6g of Mg was to 100cm3 of 1 moldm3 H2 SO4 . What mass of Mg remained undissolved? (Mg = 24)

0.24g

2.4g

3.6g

0.36g

Answer Details

The balanced chemical equation for the reaction between magnesium (Mg) and sulfuric acid (H2SO4) is: Mg + H2SO4 -> MgSO4 + H2 According to the equation, one mole of Mg reacts with one mole of H2SO4 to produce one mole of magnesium sulfate (MgSO4) and one mole of hydrogen gas (H2). Since the concentration of the sulfuric acid is 1 moldm3, this means that there is one mole of H2SO4 in every 1 liter (1000 cm3) of solution. To determine the amount of Mg that reacts with the H2SO4, we need to use stoichiometry. One mole of Mg reacts with one mole of H2SO4, so the amount of Mg that reacts with 1 moldm3 of H2SO4 is given by: 6g / 24g/mol = 0.25 mol Since the reaction is 1:1, this means that 0.25 mol of H2SO4 is consumed in the reaction. The volume of the solution is 100cm3 (0.1 dm3), so the amount of H2SO4 in the solution is: 1 mol/dm3 x 0.1 dm3 = 0.1 mol The amount of H2SO4 that remains after the reaction is: 0.1 mol - 0.25 mol = -0.15 mol This negative value means that all of the H2SO4 was consumed in the reaction, and there is excess Mg left over. The mass of Mg that remains undissolved is given by: 0.15 mol x 24g/mol = 3.6g Therefore, the correct answer is 3.6g.

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Kinetic Theory Of Matter And Gas Laws

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Question 18 Report

30 cm3 of oxygen at 10 atmosphere pressure is placed in a 20 dm3 container. Calculate the new pressure if the temperature is kept constant.

6.7 atm

15.0 atm

6.0 atm

66.0 atm

Answer Details

Given:

Initial pressure, 𝑃1=10P1=10 atmospheres

Initial volume, 𝑉1=30 cm3V1=30cm3

Final volume, 𝑉2=20 dm3V2=20dm3

First, convert all volumes to the same units. Since 1 dm3dm3 is 1000 cm3cm3:

𝑉2=20 dm3=20×1000 cm3=20000 cm3V2=20dm3=20×1000cm3=20000cm3

Now, using Boyle's Law:

𝑃1𝑉1=𝑃2𝑉2P1V1=P2V2

Substitute the known values into the equation:

10×30=𝑃2×2000010×30=P2×20000

300=𝑃2×20000300=P2×20000

Solve for 𝑃2P2:

𝑃2=30020000P2=20000300

𝑃2=0.015 atmospheresP2=0.015atmospheres

Therefore, the new pressure if the temperature is kept constant is:

0.015 atmospheres0.015atmospheres

Read lesson note on Kinetic Theory Of Matter And Gas Laws (JAMB)

Kinetic Theory Of Matter And Gas Laws

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Question 19 Report

Which of the following compound is NOT the correct formed compound when the parent metal is heated in air?

Calcium oxide

Sodium oxide ( Na2O )

Copper (II) oxide (CuO)

tri-iron tetraoxide (Fe2O)

Answer Details

The compound that is NOT correctly formed when the parent metal is heated in air is: tri-iron tetraoxide (Fe2O). This is because the correct compound formed from the heating of iron in air is iron (III) oxide or Fe2O3. The formula for tri-iron tetraoxide is incorrect, as it implies that there are only three iron atoms in the compound when there should be four.

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 20 Report

Which of the following roles does sodium chloride play in preparation? It

reacts with glycerol

purifies the soap, accelerates the decomposition of fat and oil

separates soap from glycerol

converts the fat acid to its sodium salt

Answer Details

The role that sodium chloride (NaCl) plays in soap preparation is to separate soap from glycerol. When fats or oils are hydrolyzed with an alkali, such as sodium hydroxide (NaOH), the result is a mixture of soap and glycerol. Adding NaCl to this mixture helps to induce the precipitation of the soap, allowing it to be separated from the glycerol. This process is known as "salting out" and is used to purify the soap and remove impurities. Sodium chloride does not react with glycerol or accelerate the decomposition of fat and oil. Also, it does not convert the fatty acid to its sodium salt as this conversion is done by the alkali (such as NaOH) during the saponification process.

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Acids, Bases And Salts

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Question 21 Report

\(2\mathrm{H}_2 + \mathrm{O}_2 \rightarrow 2\mathrm{H}_2\mathrm{O}\)

From the equation above, calculate the volume of unreacted oxygen gas if a mixture of \(50\mathrm{cm}^3\) of hydroden and \(75\mathrm{cm}^3\) of oxygen are involved

85cm

^{3}

50cm

^{3}

125cm

^{3}

55cm

^{3}

Answer Details

The balanced chemical equation shows that 2 moles of hydrogen gas react with 1 mole of oxygen gas to produce 2 moles of water vapor. Therefore, the stoichiometric ratio of hydrogen to oxygen is 2:1. In this problem, there are 50cm3 of hydrogen gas and 75cm3 of oxygen gas. Since the gases are at the same temperature and pressure, their volumes are directly proportional to the number of moles of gas present. Using the stoichiometric ratio, we can calculate that the amount of oxygen gas required to react completely with 50cm3 of hydrogen gas is (1/2) * 50cm3 = 25cm3. Since there are 75cm3 of oxygen gas present, there must be (75cm3 - 25cm3) = 50cm3 of unreacted oxygen gas remaining. Therefore, the volume of unreacted oxygen gas is 50cm3. Answer: 50cm3

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Stoichiometry And Chemical Reactions

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Question 22 Report

The sulphide that is commonly used in coating electric fluorescent tubes is?

iron(ii)Sulphide

tin(ii)sulphide

Zinc Sulphide

lead(iv) Sulphide

Answer Details

The sulphide commonly used in coating electric fluorescent tubes is Zinc Sulphide. Zinc Sulphide is a type of material that glows when it is exposed to ultraviolet light. When ultraviolet light is generated inside a fluorescent tube, it excites the Zinc Sulphide particles, causing them to emit visible light. This visible light is what we see as the bright light coming from the tube. So, Zinc Sulphide acts as a phosphor and helps in producing the bright light in fluorescent tubes.

Read lesson note on Acids, Bases And Salts (JAMB)

Acids, Bases And Salts

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Question 23 Report

The oxidation number of oxygen in BaO2 is

-2

-4

-1

Answer Details

To determine the oxidation number of oxygen in BaO2, we can use the fact that the overall charge of a compound must be zero. Barium (Ba) is a Group 2 element and has an oxidation state of +2. The compound BaO2 has no net charge, so the sum of the oxidation states of all the atoms must be zero. Let x be the oxidation state of oxygen in BaO2. Therefore, we have: (+2) + 2(x) = 0 Solving for x, we get: x = -1 Therefore, the oxidation number of oxygen in BaO2 is -1.

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Oxidation And Reduction

Redox Reactions

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Question 24 Report

\( \mathrm{Zn + 2HCl \rightarrow ZnCl_2 + H_2} \)

What happens to zinc in the above reaction?

oxidized

a reactant

reduced

a metal

Answer Details

In the above reaction, zinc (Zn) reacts with hydrochloric acid (HCl) to form zinc chloride (ZnCl2) and hydrogen gas (H2). The chemical equation for the reaction is: Zn + 2HCl → ZnCl2 + H2 During the reaction, zinc atoms lose two electrons each and get oxidized to form positively charged zinc ions (Zn2+), as they react with the hydrogen ions (H+) from the hydrochloric acid to form zinc chloride. The hydrogen ions, on the other hand, gain an electron each and get reduced to form hydrogen gas molecules (H2). Therefore, in the given reaction, zinc is getting oxidized, as it loses electrons and forms a positively charged ion. Hence, the correct option is "oxidized."

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Oxidation And Reduction

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Question 25 Report

Which of the following substances is not a homogeneous mixture?

filtered sea water

soft drinks

flood water

writing ink

Answer Details

The substance that is not a homogeneous mixture is flood water. Flood water is typically a mixture of various substances, such as sediment, dirt, debris, and organic matter, that have been carried along by the water. As such, flood water is usually a heterogeneous mixture, meaning that it does not have a uniform composition throughout. In contrast, filtered sea water, soft drinks, and writing ink are all examples of homogeneous mixtures, where the components are evenly distributed and the mixture has a uniform composition throughout.

Read lesson note on Separation Of Mixtures And Purification Of Chemical Substances (JAMB)

Separation Of Mixtures And Purification Of Chemical Substances

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Question 26 Report

Which of the following statement is TRUE of the complete hydrolysis of a glyceride by sodium hydroxide?

3 moles of NaOH are required for each mole of glyceride

3 moles of glycerol are produced

only one mole of soap is formed

concentrated H2SO4 is essential for the completion of the reaction.

Answer Details

The statement that is TRUE of the complete hydrolysis of a glyceride by sodium hydroxide is: - 3 moles of NaOH are required for each mole of glyceride. During the hydrolysis of a glyceride (a triglyceride), the ester bonds between the fatty acid chains and glycerol are broken by the action of a strong base like sodium hydroxide. This results in the formation of glycerol and the corresponding salts of fatty acids, which are commonly known as "soaps." The reaction can be represented by the following equation: Triglyceride + 3 NaOH → 3 soap + glycerol As per the equation, 3 moles of NaOH are required to hydrolyze one mole of glyceride, and 3 moles of soap and one mole of glycerol are produced. The use of concentrated sulfuric acid (H2SO4) is not essential for the completion of the reaction, but it can be used as a catalyst to speed up the reaction.

Read lesson note on Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

Chemistry Of Carbon Compounds (Nigeria Only)

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Question 27 Report

A quantity of air passed through a weighted amount of alkaline pyrogallol. An increase in the weight of the pyrogallol would result from the absorption of

nitrogen

neon

argon

oxygen

Answer Details

When air is passed through alkaline pyrogallol, the oxygen in the air is absorbed by the pyrogallol, resulting in an increase in the weight of the pyrogallol. The other gases in air, namely nitrogen, neon, and argon, do not react with pyrogallol under these conditions. Therefore, the answer is oxygen.

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Air

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Question 28 Report

What volume of (dm\(^{3}\)) of water will be added to 10dm\(^{3}\) of 2.0 mol/dm\(^{3}\) HCL acid solution to give a final solution of 0.5 mol/dm\(^{3}\)?

Answer Details

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Question 29 Report

Hard water is water with high concentrations of dissolved ions, in particular calcium and

magnesium ions

nitrogen ions

phosporus ions

helium ions

Answer Details

Hard water is water that contains high amounts of dissolved minerals, specifically calcium and magnesium ions. These minerals come from the rocks and soil that the water flows through and can accumulate in the water as it travels to your home. When you use hard water, it can leave mineral deposits on your pipes, fixtures, and appliances, which can reduce their efficiency and lifespan. It can also make soap less effective and leave your skin feeling dry and itchy. Therefore, it is important to treat hard water if it is a problem in your area.

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Solubility Of Substances (Ghana Only)

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Question 30 Report

A piece of radioactive element has initially 8.0×10^22 atoms. The half life of two days after 16 days the number of atom is

5×10^21

5×10^22

25×10^21

25×10^22

Answer Details

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Kinetic Theory Of Matter And Gas Laws

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Question 31 Report

In the preparation of salts, the method employed will depend on the?

composition

dissociating ability

stability to heat

precipitating ability

Answer Details

The method employed in the preparation of salts will depend on the composition of the salt. Different salts have different chemical properties, and the method used to prepare them will depend on these properties. For example, some salts can be easily dissolved in water, while others are not very soluble and may require the use of a different solvent or special conditions to dissolve. The dissociating ability, stability to heat, and precipitating ability of the salt may also play a role in determining the preparation method, but the most important factor is the composition of the salt.

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Acids, Bases And Salts

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Question 32 Report

An organic compound contains 69% carbon, 15.3% hydrogen and 30.7% oxygen. Calculate the the empirical formula [C=12, H = 1, O = 16]

_{4}

_{1} 2

_{3}

_{9}

_{4}

_{9}

_{3}

_{8}

Answer Details

View Answer

Question 33 Report

Which of the following does NOT contain aluminum as a component?

Over-head cables

Duralumin

Container for caustic soda

Container for trioxonitrate (v) acid

Answer Details

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 34 Report

GAS	\( \mathrm{CO_2} \)	\( \mathrm{N_2} \)	\( \mathrm{O_2} \)
% BY VOLUME	4	72	24

The above table shows the compositions of the atmosphere of planet X. Which of these gases are present in higher percentages on earth?

_{2}

and O

_{2}

_{2}

and CO

_{2}

_{2}

, O

_{2}

and N

_{2}

_{2}

and N

_{2}

Answer Details

Read lesson note on Separation Of Mixtures And Purification Of Chemical Substances (JAMB)

Separation Of Mixtures And Purification Of Chemical Substances

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Question 35 Report

Ethene, when passed into concentrated H2SO4, is rapidly absorbed. The product is diluted with water and then warmed to produce

Ethanol

diethyl ether

ethanal

diethyl sulphate

Answer Details

When ethene is passed into concentrated H2SO4, it undergoes electrophilic addition reaction to form ethyl hydrogen sulfate as the product. The reaction mixture is then diluted with water and warmed to produce ethanol as the main product. Therefore, the answer is ethanol.

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Question 36 Report

\( \mathrm{SO_2 + O_2 \rightarrow 2SO_3} \)

In the reaction above, the most suitable catalyst is?

chromium(vi)oxide

iron(iii)oxide

copper(i)oxide

vanadium(v)oxide

Answer Details

The most suitable catalyst for the given reaction is vanadium(V)oxide (V2O5). Vanadium(V)oxide is a commonly used catalyst for the oxidation of sulfur dioxide (SO2) to sulfur trioxide (SO3). The reaction is an exothermic reaction, and it occurs at high temperatures (around 450-500°C) in the presence of a catalyst. V2O5 is an effective catalyst for this reaction because it has a high surface area and can provide active sites for the reaction to occur. The vanadium ions in the V2O5 catalyst undergo redox reactions with the sulfur dioxide and oxygen molecules, which promotes the formation of sulfur trioxide. Chromium(VI)oxide and iron(III)oxide are not suitable catalysts for this reaction because they are not effective at promoting the oxidation of sulfur dioxide to sulfur trioxide. Copper(I)oxide can be used as a catalyst for the reaction, but it is not as effective as vanadium(V)oxide.

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Question 37 Report

The IUPAC name for CICH2-CH2-CH2-OH is

1-chloropropan-3-ol

3-chloropropan-1-ol

1 cholorpropano

3-chloropropanol

Answer Details

The IUPAC name for CICH2-CH2-CH2-OH is 3-chloropropan-1-ol. To name the compound using the IUPAC nomenclature system, we start by identifying the longest continuous chain of carbon atoms that contains the functional group (-OH). In this case, the longest chain contains three carbon atoms, so the root name is propane. Next, we identify the position of the substituent (-Cl) on the chain. The substituent is attached to the third carbon atom in the chain, so the name of the compound becomes 3-chloropropane. Finally, we add the suffix -ol to indicate that the compound contains an alcohol functional group (-OH), so the complete name of the compound is 3-chloropropan-1-ol. Therefore, the correct answer is 3-chloropropan-1-ol.

Read lesson note on Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

Chemistry Of Carbon Compounds (Nigeria Only)

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Question 38 Report

The function of sulphur during the vulcanization of rubber is to

act as a catalyst for the polymerization of rubber molecules

convert rubber from thermosetting to thermoplastic polymer

form chains which bind rubber molecules together

break down rubber polymer molecules

Answer Details

The function of sulphur during the vulcanization of rubber is to form chains which bind rubber molecules together.

Read lesson note on Rates Of Chemical Reaction (JAMB)

Read lesson note on Acids, Bases And Salts (JAMB)

Rates Of Chemical Reaction

Acids, Bases And Salts

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Question 39 Report

One of the active components of baking powder is

MgSO4

NaHCO3

CaSO4

NaCl

Answer Details

The active component of baking powder is sodium bicarbonate (NaHCO3). It is responsible for the leavening or rising of baked goods by releasing carbon dioxide gas when it reacts with an acid. Other ingredients in baking powder, such as monocalcium phosphate and sodium aluminum sulfate, provide the acid component for the reaction to occur. Magnesium sulfate (MgSO4) and calcium sulfate (CaSO4) are not typically used in baking powder, and sodium chloride (NaCl) is simply table salt and not an active ingredient in leavening.

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Acids, Bases And Salts

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Question 40 Report

\(\mathrm{N_2O_4}\) ? \(2\mathrm{NO_2}\) (? = -ve)

From the reaction above, which of these conditions would produce the highest equilibrium yield for \(\mathrm{N_2O_4}\)?

Low temperature and high pressure

Low temperature and low pressure

high temperature and low pressure

high temperature and high pressure

Answer Details

The highest equilibrium yield of N2O4 would be produced at low temperature and low pressure. In a chemical reaction, the position of the equilibrium can be influenced by changing the temperature or pressure. A decrease in temperature or an increase in pressure favors the side of the reaction with the fewer moles of gas (in this case, N2O4). This means that, if the temperature is low and the pressure is low, there will be more N2O4 at equilibrium, as the reaction will shift to the right to counteract the reduction in the concentration of N2O4. So, low temperature and low pressure would produce the highest equilibrium yield of N2O4.

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Chemical Combination

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