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

2KClO3(g) MNO3? 2KCl(s) + 3O2(g) The importance of the catalyst in the reaction above is that

the reaction takes place more rapidly at a lower temperature

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

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

concentrated tetraoxosulphate (VI) acid

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

position of the metal in the electrochemical series

position of the metal in the periodic table

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 and attraction are in equilibrium

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

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

The ionic radii of metals are usually

greater than their atomic radii

unaffected by the charge on the ion

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)

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

separating a mixture by distillation

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

JAMB UTME - Chemistry - 2018 | Green Bridge CBT

Question 1 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

Metals And Their Compounds

Non-metals And Their Compounds

View Answer

Question 2 Report

Which of the following are mixtures?

I. Petroleum

II. Rubber latex

III. Vulcanizer's solution

IV. Carbon sulphide

I, II and III

I, II and IV

I and II only

I and IV

Separation Of Mixtures And Purification Of Chemical Substances

View Answer

Question 3 Report

What volume of oxygen will remain after reacting 8cm of hydrogen gas with 20cm of oxygen gas

10cm

^{3}

12cm

^{3}

14cm

^{3}

16cm

^{3}

Kinetic Theory Of Matter And Gas Laws

Energy And Energy Changes

View Answer

Question 4 Report

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

increase with an increase in temperature

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 5 Report

From the graph above, it may be concluded that

AgNO

_{3}

is probably not soluble at 1100

NaCl is insoluble in water

Pb(NO

_{3}

)

_{2}

is more soluble than KCIO

_{3}

The solubility of KCIO

_{3}

exceeds that of NaCl at all temperature

Solubility Of Substances (Ghana Only)

Solutions

View Answer

Question 6 Report

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

carbon-14

phosphorus-32

cobalt

iodine-131

Chemistry Of Carbon Compounds (Nigeria Only)

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Question 7 Report

ME + nF -----> pG + qH

In the equation shown, the equilibrium constant is given by?

\frac{[E]^{m} [F]}{[G]^{p} [H]^{q}}

\frac{[E] [F]}{[G] [H]}

\frac{[G]^{p} [H]^{p}}{[E]^{m} [F]^{n}}

\frac{[G] [H]}{[E] [F]}

Answer Details

The equilibrium constant for a chemical reaction is a measure of the balance between the reactants and products of a reaction at a particular temperature. The equilibrium constant is given by the ratio of the product of the concentration of the products raised to their stoichiometric coefficients, to the product of the concentration of the reactants raised to their stoichiometric coefficients. In the equation ME + nF -> pG + qH, the correct expression for the equilibrium constant is [G]^p * [H]^q / [E]^m * [F]^n, represented by.

Read lesson note on Chemical Kinetics And Equilibrium Systems (Ghana Only) (WAEC)

Read lesson note on Structure Of The Atom (WAEC)

Chemical Kinetics And Equilibrium Systems (Ghana Only)

Structure Of The Atom

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Question 8 Report

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

0°C

-100°C

-273°C

-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 9 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

Acids, Bases And Salts (Ghana Only)

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Question 10 Report

The periodic classification is an arrangement of the elements

atomic weights

isotopic weights

molecular weights

atomic numbers

Answer Details

The periodic classification is an arrangement of the elements based on their atomic numbers. The periodic table is a chart that lists all the known chemical elements in order of increasing atomic number, arranged in rows and columns according to their electronic structure and chemical properties. The atomic number of an element is the number of protons in the nucleus of an atom of that element. Each element has a unique atomic number, which determines its position in the periodic table. The elements are arranged in rows called periods, and in columns called groups or families. Elements in the same group have similar properties because they have the same number of valence electrons, which are the electrons in the outermost shell of the atom. The periodic table is an incredibly useful tool for chemists because it allows them to predict the properties of elements based on their position in the table. For example, elements in the same group tend to form similar compounds, so if you know the properties of one element in a group, you can often predict the properties of the other elements in that group. In summary, the periodic classification is an arrangement of the elements based on their atomic numbers. The periodic table is a chart that organizes the elements into rows and columns based on their electronic structure and chemical properties, allowing scientists to make predictions about the behavior of the elements based on their position in the table.

Read lesson note on Atomic Structure And Bonding (JAMB)

Atomic Structure And Bonding

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Question 11 Report

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

saponification

dehydration

esterification

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 12 Report

Which of the compounds is composed of Al, Si, O and H?

Epson salt

Limestone

Clay

Urea

Answer Details

The compound composed of Al, Si, O and H is clay. Clay is a type of sedimentary rock that is made up of very small mineral particles, including hydrated aluminum silicates and other minerals such as quartz and feldspar. These minerals are rich in aluminum, silicon, oxygen, and hydrogen, which gives clay its unique chemical composition. Clay is formed through a process of weathering and erosion of rocks containing these minerals over a long period of time. As water and other natural forces break down the rocks, the mineral particles become suspended in water and are eventually deposited in sedimentary layers. Over time, these layers become compacted and cemented together, forming the solid clay deposits we see today. Therefore, the answer is option C: Clay.

Read lesson note on Chemical Combination (JAMB)

Chemical Combination

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Question 13 Report

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

be bleached

turn green

turn red

turn blue

Acids, Bases And Salts

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Question 14 Report

The collision theory explains reaction rates in terms of

size of the product

frequency of collision of the reactants

size of reactant

frequency of collision of the products

Answer Details

The collision theory explains reaction rates in terms of the frequency of collision of the reactants. In other words, the theory suggests that for a chemical reaction to occur, the reactant particles must collide with sufficient energy and with the correct orientation. The frequency of these collisions is an important factor in determining the rate of the reaction. The more frequently the reactant particles collide, the more likely it is that they will react and form products. Therefore, increasing the frequency of collisions between reactant particles can increase the rate of a chemical reaction. The size of the reactants or the products does not play a significant role in the collision theory.

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

How many atoms are present in 6.0g of magnesium? [Mg = 24, N.A = \(6.02 \times 10^{23}\) mol]

1.20 x 10

^{22}

2.4 x 10

^{22}

1.51 x 10

^{22}

3.02 x 10

^{22}

Atomic Structure And Bonding

View Answer

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

oxidizing properties of ammonia

Chemical Combination

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Question 17 Report

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

carbon (II) oxide

sulphur (IV) oxide

carbon (IV) oxide

sulphur (VI) oxide

Kinetic Theory Of Matter And Gas Laws

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Question 18 Report

If 1 litre of 2.2M sulphuric acid is poured into a bucket containing 10 litres of water and the resulting solution mixed thoroughly, the resulting sulphuric acid concentration will be

2.2M

1.1M

0.22M

0.11M

Answer Details

When 1 liter of 2.2M sulphuric acid is added to 10 liters of water, the total volume of the resulting solution is 11 liters. To find the resulting concentration of sulphuric acid, we need to use the equation: M1V1 = M2V2 where M1 is the initial concentration, V1 is the initial volume, M2 is the final concentration, and V2 is the final volume. We can plug in the values we know: M1 = 2.2M (the initial concentration of the sulphuric acid) V1 = 1L (the initial volume of the sulphuric acid) M2 = ? (the final concentration we're trying to find) V2 = 11L (the final volume of the resulting solution) Solving for M2, we get: M2 = (M1 x V1) / V2 M2 = (2.2M x 1L) / 11L M2 = 0.2M Therefore, the resulting sulphuric acid concentration is 0.2M or 0.2 moles per liter. In summary, when 1 liter of 2.2M sulphuric acid is mixed with 10 liters of water, the resulting sulphuric acid concentration is diluted to 0.2M. This is because the total volume of the resulting solution is greater than the initial volume of the sulphuric acid, which leads to a decrease in concentration.

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

Acids, Bases And Salts (Ghana Only)

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Question 19 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

Ca

Al

Po

Chemical Bonds (Nigeria Only)

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Question 20 Report

An element used in the production of matches is

nitrogen

aluminium

copper

sulphur

Answer Details

The element used in the production of matches is sulphur. Matches are small sticks made of wood or cardboard with a chemical mixture at one end. This chemical mixture, called the match head, contains several compounds including sulphur. When the match is struck against a rough surface, the friction generates heat that ignites the sulphur in the match head, causing a flame. This flame then ignites the other compounds in the match head, which in turn ignites the wood or cardboard stick. Sulphur is an important component of the match head because it is highly flammable and burns easily. It also helps to ignite the other compounds in the match head. However, sulphur by itself is not a good fuel, which means that it cannot sustain a flame on its own. Therefore, it needs other combustible materials, such as potassium chlorate or phosphorus, to make the match head burn. Overall, sulphur plays a crucial role in the chemistry of matches and allows us to easily start fires for various purposes.

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

Non-metals And Their Compounds

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Question 21 Report

The alkanoic acid found in human sweat is

CH

_{3}

-COOH

CH

_{3}

—CH

_{2}

—COOH

H-COOH

CH

_{3}

Answer Details

The alkanoic acid found in human sweat is CH3CH2COOH, also known as propionic acid. Sweat is composed of various substances such as water, electrolytes, and waste products. One of these waste products is an oily substance called sebum, which is secreted by the sebaceous glands in the skin. When sebum breaks down, it forms various fatty acids, including propionic acid. Propionic acid has a slightly pungent odor, which is why sweat can sometimes smell sour or cheesy. However, the presence of propionic acid in sweat is actually beneficial, as it has antimicrobial properties that help to prevent the growth of harmful bacteria on the skin. In summary, the alkanoic acid found in human sweat is propionic acid, which is a fatty acid produced when sebum breaks down. Its antimicrobial properties help to keep the skin healthy.

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

Acids, Bases And Salts

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Question 22 Report

Sieving is a technique used to separate mixtures containing solid particles of

small sizes

large sizes

different sizes

the same size

Answer Details

Sieving is a technique used to separate mixtures containing solid particles of different sizes. A sieve is a mesh or perforated screen that is used to separate particles based on their size. The mixture is poured onto the sieve, and the particles that are too large to pass through the holes are left on top, while the smaller particles fall through the holes and are collected below. This process allows for the separation of the different-sized particles, making it easier to purify or further process the mixture.

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 23 Report

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

coordinate

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 24 Report

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

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

Answer Details

During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment, the litmus will turn red and oxygen gas will be evolved. This is because during electrolysis, the positively charged copper ions (Cu2+) in the copper II sulphate solution are attracted to the negative cathode electrode, where they gain electrons and are reduced to form solid copper. At the same time, the negatively charged sulphate ions (SO42-) are attracted to the positive anode electrode, where they lose electrons and are oxidized to form oxygen gas and water. The litmus added to the anode compartment turns red because of the formation of oxygen gas, which is a highly reactive oxidizing agent that can react with the litmus to cause it to turn red. No hydrogen gas is evolved because hydrogen is produced at the cathode, which is in a separate compartment from the anode where the litmus is added.

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Electrolysis

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Question 25 Report

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

oxygen is a component of air

air is an impure substance

Separation Of Mixtures And Purification Of Chemical Substances

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Question 26 Report

The Sulphide which is insoluble in dilute hydrochloric acid is

FeS

CuS

ZnS

Na2S

Answer Details

The sulphide which is insoluble in dilute hydrochloric acid is Copper Sulphide (CuS). When metal sulphides react with hydrochloric acid, they undergo an acid-base reaction to produce hydrogen sulphide gas and the corresponding metal chloride. For example, when Iron Sulphide (FeS) reacts with hydrochloric acid, it forms hydrogen sulphide gas (H2S) and iron chloride (FeCl2) as follows: FeS + 2HCl → H2S + FeCl2 However, Copper Sulphide (CuS) does not react with dilute hydrochloric acid, as it is insoluble in this acid. This is due to the fact that CuS is a much less reactive metal sulphide compared to FeS and ZnS, and therefore it does not undergo an acid-base reaction with dilute hydrochloric acid. In summary, CuS is the sulphide which is insoluble in dilute hydrochloric acid due to its low reactivity with acids.

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 27 Report

The lUPAC name for

1-methyl pentane

3-methylbutane

2-methylbutane

1-dimethyl propane

View Answer

Question 28 Report

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

aniline

xylene

phenol

toluene

Chemistry Of Carbon Compounds (Nigeria Only)

View Answer

Question 29 Report

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

196

49

106

82

Kinetic Theory Of Matter And Gas Laws

View Answer

Question 30 Report

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

crystal lattice formation

covalent bond formation

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 31 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

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.

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

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

Read lesson note on Energy And Energy Changes (WAEC)

Kinetic Theory Of Matter And Gas Laws

Chemical Bonds (Nigeria Only)

Energy And Energy Changes

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Question 32 Report

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

1

2

3

4

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 33 Report

The hydrogen ion concentration of a sample of orange juice is 2.0 X 10\(^{-11}\)moldm\(^{-3}\). What is its p\(^{OH}\)? [log102 = 0.3010]

3.30

13.00

10.70

11.30

Acids, Bases And Salts (Ghana Only)

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Question 34 Report

Aluminium does not react with either dilute or concentrated trioxonitrate (V) acid because

it is insoluble in either dilute or concentrated trioxonitrate (V) acid

it is lower than hydrogen in the electrochemical series

the reaction with trioxonitrate (V) acid has a light activation energy

an insoluble oxide is formed on its surface which renders it passive

Non-metals And Their Compounds

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Question 35 Report

On which of the following is the solubility of a gaseous substance dependent?

I. Nature of solvent

II. Nature of solute

III. Temperature

IV. Pressure

I, II, III and IV

I and II only

II only

I, III and IV only

Solubility

View Answer

Question 36 Report

The elements in the periodic table are listed in order of increasing

relative atomic number

atomic mass

relative isotopic mass

nuclear charge

Atomic Structure And Bonding

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Question 37 Report

Which of the following statements is correct about the periodic table?

Elements in the same period have the same number of valence electrons

The valence electrons of the elements in the same period increase progressively across the period

Elements in the same group have the same number of electron shells

The non-metallic Properties of the elements tend to decrease across each period

Atomic Structure And Bonding

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Question 38 Report

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

298K

546K

819K

1092K

Kinetic Theory Of Matter And Gas Laws

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Question 39 Report

Calculate the pH of \(0.05\ \mathrm{mol\,dm^{-3}}\ \mathrm{H_2SO_4}\)

1.30

1.12

1.00

0.30

Answer Details

To solve this problem, we need to use the formula for calculating the pH of a solution, which is: pH = -log[H+] where [H+] is the concentration of hydrogen ions in moles per liter. The given chemical equation is: H2SO4 + 2H2O → 2H3O+ + SO42- From this equation, we can see that one molecule of sulfuric acid (H2SO4) can donate two hydrogen ions (H+) to the solution, which means that the concentration of hydrogen ions is twice the concentration of sulfuric acid. Therefore, the concentration of hydrogen ions in this solution is: [H+] = 2 x 0.05 moldm^-3 = 0.1 moldm^-3 Now we can use the formula for pH: pH = -log[H+] pH = -log(0.1) pH = 1.00 Therefore, the pH of the solution is 1.00.

Read lesson note on Periodic Chemistry (Ghana Only) (WAEC)

Periodic Chemistry (Ghana Only)

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Question 40 Report

The knowledge of half-life can be used to

Create an element

Detect an element

Split an element

Irradiate an element

Kinetic Theory Of Matter And Gas Laws

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