During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment

the litmus turns red and oxygen is evolved

the litmus turns blue but no gas is evolved

the litmus turns blue and oxygen is evolved

the litmus turns blue and hydrogen is evolved

the litmus turns red and oxygen is evolved

Methanoic acid mixes with water in all proportions and has about the same boiling point as water. Which of the following methods would you adopt to obtain pure water from a mixture of Sand, water and methanoic acid?

Filtration followed by distillation

Neutralization with sodium hydroxide followed by distillation

Neutralization with sodium hydroxide followed by filtration

The presence of ammonia gas in a desiccator can exclusively be removed by

concentrated tetraoxosulphate (VI) acid

Suitable reagents for the laboratory preparation nitrogen are

sodium dioxonitrate(III) and ammonium chloride

sodium trioxonitrate(V) and ammonium chloride

sodium chloride and ammonium trioxonitrate(V)

sodium chloride and ammonium di-ozonitrate(III)

The collision theory explains reaction rates in terms of

frequency of collision of the reactants

frequency of collision of the products

The conductivity of an acid solution depends on the

amount of ions present and their mobilities

Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,

Q will form an electrovalent bond with S

P will form an electrovalent bond with R

Q will form a covalent bond with S

R will form an electrovalent bond with S

Q will form an electrovalent bond with S

The situation obtained when a perfect gas expands into a vacuum is

ΔH is zero and T Δ S is positive

ΔH is positive and TΔ S is zero

ΔH is positive and T Δ S is negative

ΔH is negative and TΔ S is zero

ΔH is zero and T Δ S is positive

In the laboratory preparation of oxygen, the gas cannot be collected by displacement of air because

the density of oxygen is greater than that of air

the density of air is nearly the same as that of oxygen

JAMB UTME - Chemistry - 2018 | Green Bridge CBT

Question 1 Report

The derivative of benzene that can be used in making explosives is

aniline

xylene

phenol Correct answer

toluene

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

In the shown experiment (Fig. 1) the litmus paper will initially

be bleached

turn green

turn red

turn blue Correct answer

Answer Details

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

Acids, Bases And Salts

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Question 3 Report

The boiling of fat and aqueous caustic soda is referred to as

hydrolysis

esterification

acidification

saponification Correct answer

Answer Details

The boiling of fat and aqueous caustic soda is referred to as saponification. Saponification is the process of converting fat into soap through a reaction with an alkaline substance, such as caustic soda. The reaction results in the formation of soap (a salt of a fatty acid) and glycerol. This process is important in the manufacture of soap, as it allows the fat to be converted into a useful cleaning product.

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Acids, Bases And Salts

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Question 4 Report

Diamond is a bad conductor of electricity because its bonding electrons are used in

crystal lattice formation

covalent bond formation Correct answer

metallic bond formation

coordinate bond formation

Answer Details

Diamond is a bad conductor of electricity because of its unique structure and bonding. The carbon atoms in diamond form a covalent network, where each carbon atom is bonded to four other carbon atoms. These bonds are strong and hold the atoms in a rigid three-dimensional structure called a crystal lattice. In a covalent bond, atoms share electrons to form a stable compound. In diamond, each carbon atom shares its valence electrons with four neighboring carbon atoms, forming a very strong covalent bond. All the valence electrons in the crystal lattice are used in covalent bond formation, which means there are no free or mobile electrons to carry an electric current. In other words, the electrons are tightly held in the covalent bonds, making it difficult for them to move around the crystal lattice and conduct electricity. In contrast, metals conduct electricity well because they have delocalized or free electrons that can move through the lattice of positively charged ions. So, diamond, being a covalent network solid, does not have free electrons that can carry an electric current, which is why it is a bad conductor of electricity.

Read lesson note on Atomic Structure And Bonding (JAMB)

Atomic Structure And Bonding

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Question 5 Report

Which of these alloys contains copper?

solder

steel

permallory

bronze Correct answer

Answer Details

Bronze is the alloy that contains copper. Bronze is a metal alloy composed of copper and typically other elements such as tin, aluminum, silicon, or nickel. It is known for its strength, durability, and corrosion resistance. In fact, bronze is one of the earliest alloys created by humans, and it has been used for thousands of years to make tools, weapons, and decorative objects. Solder is an alloy of lead, tin, and sometimes other metals that is used to join metals together by melting the solder and allowing it to flow into the joint. Steel is an alloy of iron and carbon, and sometimes other elements like chromium, nickel, or manganese, that is known for its strength and durability. Permallory is a nickel-iron alloy with high magnetic permeability and low coercive force, which makes it useful in the production of electrical and electronic equipment. None of these alloys contain copper.

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 6 Report

A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by

boiling the water

adding excess calcium hydroxide

adding a calculated amount of calcium hydroxide

adding sodium carbonate Correct answer

Answer Details

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

Acids, Bases And Salts (Ghana Only)

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Question 7 Report

The number of electrons in the valence shell of an element of atomic number 14 is?

4 Correct answer

Answer Details

The number of electrons in the valence shell of an element can be determined by using the periodic table and the electron configuration of the element. The valence shell is the outermost shell that contains electrons that are involved in chemical reactions. For an element with atomic number 14, which is silicon, the electron configuration is 1s2 2s2 2p6 3s2 3p2. The valence shell of silicon is the third shell, which contains 3s2 and 3p2 electrons. Therefore, the number of electrons in the valence shell of silicon is 4 electrons.

Read lesson note on Atomic Structure And Bonding (JAMB)

Atomic Structure And Bonding

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Question 8 Report

Which of these sources of water may likely contain the least concentration of Ca\(^{2+}\) and Mg\(^{2+}\)?

Spring water

River water

Tap water Correct answer

Sea water

Answer Details

The source of water that is likely to contain the least concentration of Ca2+ and Mg2+ is tap water. Tap water is treated and processed before it is made available for consumption, which often involves removing minerals such as calcium and magnesium. Spring water and river water, on the other hand, are naturally occurring and generally contain higher levels of minerals. Sea water has the highest concentration of minerals, including Ca2+ and Mg2+.

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Water

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Question 9 Report

The ionic radii of metals are usually

greater than their atomic radii

unaffected by the charge on the ion

the same as their atomic radii

less than their atomic radii Correct answer

Answer Details

The ionic radii of metals are usually smaller than their atomic radii. The size of an atom is determined by the distance between the nucleus and the outermost electrons, which is known as the atomic radius. When a metal atom loses one or more electrons to form a positive ion (or cation), the resulting ion has a smaller size than the original atom. This is because the positive charge of the ion attracts the remaining electrons closer to the nucleus, making the ion smaller in size. So, when a metal forms a cation, its ionic radius is typically smaller than its atomic radius. This is a general trend in the periodic table, although there are some exceptions.

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Atomic Structure And Bonding

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Question 10 Report

The constituent common to duralumin and alnico is

Al Correct answer

Answer Details

The common constituent found in both duralumin and alnico is aluminum (Al). Duralumin is an alloy made up of aluminum, copper, manganese, and magnesium. It is known for its high strength and light weight, making it useful in various applications such as aerospace and construction. Alnico, on the other hand, is an alloy made of aluminum, nickel, cobalt, iron, and small amounts of other elements. It is used in the production of strong permanent magnets for various applications such as in motors, generators, and loudspeakers. So, even though duralumin and alnico have different properties and uses, they both contain the element aluminum.

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 11 Report

\(2\mathrm{SO}_2\,(g) + \mathrm{O}_2\,(g) \leftrightarrow 2\mathrm{SO}_3\,(g)\quad \Delta H = -395.7\mathrm{kJmol}^{-1}\)

In the equation, an increase in temperature will shift the equilibrium position to the

left and equilibrium constant decreases Correct answer

left and equilibrium constant increases

right and equilibrium constant increases

right and equilibrium constant decreases

Answer Details

Read lesson note on Chemical Equilibria (JAMB)

Chemical Equilibria

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Question 12 Report

The Consecutive members of an alkane homologous series differ by

_{2}

Correct answer

_{3}

_{n}

_{n}

Answer Details

The consecutive members of an alkane homologous series differ by a CH2 unit. This means that each successive member of the alkane series has one more CH2 unit than the previous member. For example, consider the simplest alkane, methane (CH4). The next member of the series is ethane (C2H6), which differs from methane by one CH2 unit. The next member after that is propane (C3H8), which differs from ethane by another CH2 unit. This pattern continues for all members of the alkane homologous series. The reason for this is that each carbon atom in the alkane chain must be bonded to four other atoms, which are usually hydrogen atoms. This means that each carbon atom in the chain can only bond to one other carbon atom. Therefore, the length of the alkane chain can only increase by adding CH2 units to the end of the chain. In summary, the consecutive members of an alkane homologous series differ by a CH2 unit because this is the only way to add length to the alkane chain while maintaining the required number of bonds for each carbon atom in the chain.

Read lesson note on Chemical Equilibria (JAMB)

Chemical Equilibria

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Question 13 Report

Which of the following is an example of a chemical change?

dissolution of salt in water

rusting of iron Correct answer

melting of ice

separating a mixture by distillation

Answer Details

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

Acids, Bases And Salts

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Question 14 Report

According to Charles' law, the volume of a gas becomes zero at

0°C

-100°C

-273°C Correct answer

-373°C

Answer Details

Charles' law states that the volume of a gas is directly proportional to its temperature, provided that the pressure remains constant. This means that as the temperature of a gas increases, its volume also increases. However, it is important to note that this law only applies to ideal gases, which are theoretical gases that perfectly follow the laws of thermodynamics. According to Charles' law, the volume of a gas becomes zero at absolute zero, which is approximately -273°C. At this temperature, the gas particles would have no kinetic energy and would be in their lowest energy state. The volume of a real gas would not actually become zero at absolute zero because the gas particles would have some residual intermolecular interactions that would prevent them from completely collapsing to a single point.

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

Kinetic Theory Of Matter And Gas Laws

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Question 15 Report

To what temperature must a gas at 273k be heated in order to double both its volume and pressure?

298K

546K

819K

1092K Correct answer

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 16 Report

(I). \(3\mathrm{CuO}(s) + 2\mathrm{NH}_3(g) \longrightarrow 3\mathrm{Cu}(s) + 3\mathrm{H}_2\mathrm{O}(l) + \mathrm{N}_2(g)\)

(II). \(2\mathrm{NH}_3(g) + 3\mathrm{Cl}_2(g) \longrightarrow 6\mathrm{HCl}(g) + \mathrm{N}_2(g)\)

(III). \(4\mathrm{NH}_3(g) + 3\mathrm{O}_2(g) \longrightarrow 6\mathrm{H}_2\mathrm{O}(l) + \mathrm{N}_2(g)\)

The reactions represented by the equations above demonstrate the

basic properties of ammonia

acidic properties of ammonia

reducing properties of ammonia Correct answer

oxidizing properties of ammonia

Answer Details

Read lesson note on Chemical Combination (JAMB)

Chemical Combination

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Question 17 Report

Which of the following separation techniques can be employed in obtaining solvent from its solution?

Evaporation

Distillation Correct answer

Filtration

Precipitation

Answer Details

The separation technique that can be employed in obtaining a solvent from its solution is evaporation. Evaporation is a process that involves heating a solution to vaporize the solvent, leaving behind the solute. The vaporized solvent can then be condensed and collected as a pure liquid. This technique is commonly used in industry and laboratory settings to recover solvents from solutions, as it is a simple and effective way to purify liquids. Distillation can also be used to separate a solvent from a solution, but it is a more complex process that involves boiling the solution and then condensing the vapors in a separate apparatus. Filtration and precipitation are not suitable for separating a solvent from a solution, as they are primarily used to separate solid particles from a liquid mixture.

Read lesson note on Solubility (JAMB)

Solubility

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Question 18 Report

What is the PH of 0.00 1 moldm\(^{3}\) solution of the sodium hydroxide

11 Correct answer

Answer Details

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

Acids, Bases And Salts (Ghana Only)

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Question 19 Report

In the upper atmosphere, the ultra-violet light breaks off a free chlorine atom from chlorofluorocarbon molecule. The effect of this is that the free chlorine atom will

be very reactive and will attack ozone Correct answer

be non-reactive and will not attack ozone

not change the level of ozone in the atmosphere

increase the level of ozone in the atmosphere

Answer Details

The free chlorine atom that breaks off from a chlorofluorocarbon molecule will be very reactive and will attack ozone in the upper atmosphere. Ozone is a molecule made up of three oxygen atoms, and when the free chlorine atom reacts with ozone, it breaks the ozone molecule into two separate oxygen molecules. This reaction reduces the amount of ozone in the atmosphere, which is known as ozone depletion. Over time, this can lead to a thinning of the ozone layer, which protects life on Earth from harmful ultraviolet radiation from the sun.

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Environmental Pollution

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Question 20 Report

An aqueous solution of a metal salt, M. gives a white precipitate with NaOH which dissolves in excess NaOH. With aqueous ammonia, the solution of M also gives a white precipitate which dissolves in excess ammonia Therefore the cation in M is

Zn Correct answer

Answer Details

Read lesson note on Chemical Bonds (Nigeria Only) (WAEC)

Chemical Bonds (Nigeria Only)

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Question 21 Report

A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that

collisions are perfectly elastic

forces of repulsion exis Correct answer

forces of repulsion and attraction are in equilibrium

collisions are inelastic

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 22 Report

The type of bonding in \(\left[\mathrm{Cu}(\mathrm{NH}_3)_4\right]^{2+}\) is

coordinate Correct answer

electrovalent

metallic

covalent

Answer Details

The type of bonding in [Cu(NH3)4]2+ is coordinate bonding. Coordinate bonding (also known as dative covalent bonding) is a type of covalent bonding where one atom (in this case, the nitrogen atom in NH3) donates a pair of electrons to another atom or ion (in this case, the copper ion Cu2+). The donating atom is called the ligand, and the receiving atom or ion is called the central metal ion. In [Cu(NH3)4]2+, each ammonia molecule (NH3) donates a lone pair of electrons on the nitrogen atom to the copper ion, forming four coordinate bonds between the ligands and the central copper ion. The presence of coordinate bonds is indicated by the use of square brackets around the coordination compound, and the charge on the compound is indicated by the superscript outside the brackets. Therefore, the answer is option A: coordinate.

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Question 23 Report

In the reaction between sodium hydroxide and sulphuric acid solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralise 10cm3 of 1.25 molar sulphuric acid?

5cm

^{3}

10cm

^{3}

20cm

^{3}

50cm

^{3}

Correct answer

Answer Details

Read lesson note on Stoichiometry And Chemical Reactions (WAEC)

Stoichiometry And Chemical Reactions

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Question 24 Report

When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are;

nitrogen and carbondioxide

the rare gases

nitrogen and oxygen

nitrogen and the rare gases Correct answer

Answer Details

Read lesson note on Air (JAMB)

Air

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Question 25 Report

2KClO3(g) MNO3? 2KCl(s) + 3O2(g)

The importance of the catalyst in the reaction above is that

heating may not be required before the reaction takes place

the reaction is controllable even at a high temperature

the reaction produces large quantity of oxygen

the reaction takes place more rapidly at a lower temperature Correct answer

Answer Details

Read lesson note on Stoichiometry And Chemical Reactions (WAEC)

Stoichiometry And Chemical Reactions

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Question 26 Report

A given amount of gas occupies \(10.0\mathrm{dm}^{5}\) at 4atm and 273°C. The number of moles of the gas present is [Molar volume of gas at s.t.p = \(22.4\mathrm{dm}^{3}\)]

0.89 mol Correct answer

1.90 mol

3.80 mol

5.70 mol

Answer Details

The ideal gas law is PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is temperature. We can use this equation to solve for the number of moles of gas present. First, we need to convert the volume from dm5 to dm3, which is the same as liters (L). So, 10.0 dm5 is equal to 10.0/1000 = 0.01 dm3 or 0.01 L. Next, we need to convert the temperature from Celsius to Kelvin by adding 273 to get 546 K. Now we can plug in the values we have into the ideal gas law: 4 atm x 0.01 L = n x 0.0821 L·atm/K·mol x 546 K Simplifying, we get: 0.04 = n x 44.8 Solving for n, we get: n = 0.04/44.8 = 0.00089 mol Finally, we can compare this value to the molar volume of a gas at standard temperature and pressure (STP), which is 22.4 L/mol. To do this, we need to convert the volume of gas we have to STP conditions. Since the temperature is already at STP (273 K), we just need to adjust the pressure. Using the ideal gas law, we can solve for the volume at STP: 1 atm x V = 0.00089 mol x 0.0821 L·atm/K·mol x 273 K Simplifying, we get: V = 0.0224 L or 22.4 dm3 Therefore, the amount of gas present is equal to 0.00089 mol, which is less than 1 mol. So the answer is 0.89 mol.

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

Read lesson note on Stoichiometry And Chemical Reactions (WAEC)

Read lesson note on States Of Matter (WAEC)

Kinetic Theory Of Matter And Gas Laws

Stoichiometry And Chemical Reactions

States Of Matter

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Question 27 Report

The radio isotope used in industrial radiography for the rapid checking of faults in welds and casting is?

carbon-14

phosphorus-32

cobalt Correct answer

iodine-131

Answer Details

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

Chemistry Of Carbon Compounds (Nigeria Only)

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Question 28 Report

Which of the following metals cannot replace hydrogen from water or steam?

Sodium

Magnesium

Iron

Calcium Correct answer

Answer Details

Read lesson note on Metals And Their Compounds (JAMB)

Metals And Their Compounds

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Question 29 Report

The refreshing and characteristic taste of soda water and other soft drinks is as a result of the presence of

carbon(IV)oxide Correct answer

carbon(ll)oxide

soda

glucose

Answer Details

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

Acids, Bases And Salts (Nigeria Only)

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Question 30 Report

A substance that is used as a ripening agent for fruits is

ethene Correct answer

propane

methane

butane

Answer Details

The substance that is commonly used as a ripening agent for fruits is ethene. Ethene, also known as ethylene, is a natural plant hormone that is produced by fruits, especially during the ripening process. It is a colorless gas that can be easily synthesized and used as a ripening agent for fruits. When fruits are exposed to ethene, it triggers a series of biochemical reactions that accelerate the natural ripening process. This can help fruits to ripen faster and more uniformly, which is important for commercial purposes where fruits need to be sold quickly. The use of ethene as a ripening agent is regulated by food safety agencies, as excessive exposure to ethene can cause over-ripening and spoilage of fruits. However, when used in appropriate concentrations, ethene is a safe and effective way to promote the ripening of fruits.

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

Acids, Bases And Salts

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Question 31 Report

The choice of method for extracting a metal from its ores depends on the

strength of the core

position of the metal in the electrochemical series Correct answer

source of the core

position of the metal in the periodic table

Answer Details

The choice of method for extracting a metal from its ores depends on the position of the metal in the electrochemical series. The electrochemical series is a list of metals arranged in order of their ability to gain or lose electrons. The metals at the top of the series (such as sodium and potassium) are very reactive and will readily lose electrons, while those at the bottom (such as gold and platinum) are less reactive and less likely to lose electrons. The position of a metal in the electrochemical series determines the method of extraction that should be used. For example, metals at the top of the series are usually extracted by electrolysis, which involves passing an electric current through a molten compound of the metal. This process is necessary because the metals at the top of the series are very reactive and are strongly bonded to other elements in their ores. On the other hand, metals at the bottom of the series are usually extracted by reduction with carbon or hydrogen. This is because these metals are less reactive and can be separated from their ores by reacting them with a reducing agent that can take away the oxygen and other impurities. Therefore, the position of the metal in the electrochemical series is a crucial factor in determining the method of extraction that should be used to extract it from its ores.

Read lesson note on Chemical Equilibria (JAMB)

Chemical Equilibria

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Question 32 Report

The end products of burning a candle in the atmosphere are water and

carbon (II) oxide

sulphur (IV) oxide

carbon (IV) oxide Correct answer

sulphur (VI) oxide

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 33 Report

The lUPAC name for

1-methyl pentane

3-methylbutane

2-methylbutane Correct answer

1-dimethyl propane

Answer Details

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Question 34 Report

Which of the following pairs of substances will react further with oxygen to form a higher oxide?

_{2}

and H

_{2}

NO and H

_{2}

CO and CO

_{2}

_{2}

and NO Correct answer

Answer Details

Read lesson note on Oxidation And Reduction (JAMB)

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

Oxidation And Reduction

Separation Of Mixtures And Purification Of Chemical Substances

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Question 35 Report

Beryllium and Aluminium have similar properties because they

are both metals

belong to the same group

belong to the same period

are positioned diagonally to each other Correct answer

Answer Details

Read lesson note on Metals And Their Compounds (JAMB)

Read lesson note on Non-metals And Their Compounds (JAMB)

Metals And Their Compounds

Non-metals And Their Compounds

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Question 36 Report

The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as;

saponification

dehydration

esterification Correct answer

hydrolysis

Answer Details

The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as esterification. Esterification is the process of forming an ester, which is a type of organic compound, from an alcohol and an acid. The acid catalyst is used to speed up the reaction by providing a proton to the reaction mixture, which helps to form the ester. Esterification results in the loss of a water molecule from the reaction mixture, which makes the reaction a type of dehydration reaction. However, it is important to note that esterification is a specific type of dehydration reaction where the products are an ester and an alcohol. So, the answer is esterification.

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

Acids, Bases And Salts

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Question 37 Report

What mass of Cu would be produced by the cathodic reduction of \(\mathrm{Cu}^{2+}\) when 1.60A of current passes through a solution of \(\mathrm{CuSO}_{4}\) for 1 hour. (F=96500Cmol\(^{-1}\), Cu=64)

7.64g

3.82g

1.91g Correct answer

0.96g

Answer Details

The reduction reaction that occurs at the cathode during the electrolysis of CuSO4" tabindex="0" class="mjx-chtml MathJax_CHTML" id="MathJax-Element-1-Frame">4, is: Cu2+" tabindex="0" class="mjx-chtml MathJax_CHTML" id="MathJax-Element-2-Frame">2+ + 2e- -> Cu(s) From this, we can see that each Cu2+ ion requires two electrons to be reduced to copper metal. Given the current (I = 1.60 A), time (t = 1 hour = 3600 s), and Faraday's constant (F = 96500 C/mol), we can calculate the total amount of charge that passes through the solution: Q = I*t = 1.60 A * 3600 s = 5760 C Using Faraday's law, we can relate the amount of charge that passes through the solution to the number of moles of electrons transferred during the reduction reaction: n = Q/F = 5760 C / 96500 C/mol = 0.0597 mol e- Since each Cu2+ ion requires 2 electrons to be reduced to copper metal, the number of moles of copper produced is half the number of moles of electrons transferred: mol Cu = 0.0597 mol e- / 2 = 0.0299 mol Cu Finally, we can convert the moles of copper produced to grams using the molar mass of copper: mass Cu = 0.0299 mol Cu * 64 g/mol = 1.91 g Therefore, the answer is 1.91 g of Cu produced. is correct.

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Kinetic Theory Of Matter And Gas Laws

Chemical Bonds (Nigeria Only)

Energy And Energy Changes

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Question 38 Report

The solubility of the solids that dissolves in a given solvent with the liberation of heat will

increase with an increase in temperature Correct answer

decrease with an increase in temperature

decrease with a decrease in temperature

not be affected by changes in temperature

Answer Details

The solubility of solids in a given solvent is the amount of solid that can dissolve in the solvent to form a solution. When a solid dissolves in a solvent, it releases heat. The solubility of the solid in the solvent can be affected by changes in temperature. Generally, when the temperature of a solution increases, the solubility of the solid in the solvent increases as well. This is because the increased heat energy makes it easier for the solid particles to separate and dissolve in the solvent. As a result, the solubility of the solid in the solvent will increase with an increase in temperature. On the other hand, if the temperature decreases, the solubility of the solid in the solvent decreases. This is because the decreased heat energy makes it harder for the solid particles to separate and dissolve in the solvent. As a result, the solubility of the solid in the solvent will decrease with a decrease in temperature. In summary, the solubility of solids in a given solvent will generally increase with an increase in temperature and decrease with a decrease in temperature.

Read lesson note on Solubility Of Substances (Ghana Only) (WAEC)

Solubility Of Substances (Ghana Only)

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Question 39 Report

If the molecular mass of tetraoxosulphate (VI) acid is 98, calculate its vapour density

196

49 Correct answer

106

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 40 Report

An element X forms the following compounds with chlorine; \( \mathrm{XCl_4} \), \( \mathrm{XCl_3} \), \( \mathrm{XCl_2} \). This illustrates the

law of multiple proportions Correct answer

law of chemical proportions

law of simple proportions

law of conservation of mass

Answer Details

The element X forming different compounds with chlorine (XCl4, XCl3, and XCl2) illustrates the law of multiple proportions. This law states that when two elements combine to form more than one compound, the ratio of the masses of one element that combine with a fixed mass of the other element is always a whole number ratio. In this case, the ratio of chlorine to X in the different compounds (XCl4, XCl3, and XCl2) is 4:1, 3:1, and 2:1, respectively, which are all whole number ratios.

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

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Kinetic Theory Of Matter And Gas Laws

Acids, Bases And Salts (Ghana Only)

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