JAMB UTME - Chemistry - 1994

Lee Azịza

Ajụjụ 8 Ripọtì

Which of the following reagents will confirm the presence of unsaturation in a compound?

Fehling's solution

Bromine water Azịza ziri ezi

Tollen's reagent

Benedict's solution

Akọwa Nkọwa

Bromine water can confirm the presence of unsaturation in a compound. Unsaturated compounds contain multiple bonds between carbon atoms, and these double or triple bonds can readily react with bromine water (an aqueous solution of bromine) by breaking the double or triple bond and forming a colorless dibromo compound. As a result, if the compound has unsaturation, bromine water will lose its characteristic orange color upon reaction with the compound, indicating the presence of unsaturation. The other reagents listed are used for different types of chemical tests, such as reducing sugars (Fehling's and Benedict's solutions) or identifying aldehydes or ketones (Tollen's reagent).

Gụọ akwụkwọ nkuzi na Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

Lee Azịza

Ajụjụ 9 Ripọtì

For a gas, the relative molecular mass is equal to 2Y. What is Y?

The mas of the gas

The vapour density of the gas Azịza ziri ezi

The volume of the gas

The temperature of the gas

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Kinetic Theory Of Matter And Gas Laws (JAMB)

Lee Azịza

Ajụjụ 10 Ripọtì

8g CH4 occupies 11.2 dm3 at s.t.p. What volume would 22 g of CH3CH3 occupy under the same condition?

(C = 12, H = 1)

3.7 dm3

11.2 dm3 Azịza ziri ezi

22.4 dm

33.6 dm3

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Stoichiometry And Chemical Reactions (WAEC)

Stoichiometry And Chemical Reactions

Lee Azịza

Ajụjụ 11 Ripọtì

Sodium chloride has no solubility product value because of its?

saline nature

high solubility Azịza ziri ezi

low solubility

insolubility

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Acids, Bases And Salts (Ghana Only) (WAEC)

Acids, Bases And Salts (Ghana Only)

Lee Azịza

Ajụjụ 12 Ripọtì

The shape of ammonia molecule is?

trigonal planar Azịza ziri ezi

octahedral

square planar

tetrahedral

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Atomic Structure And Bonding (JAMB)

Lee Azịza

Ajụjụ 13 Ripọtì

A major effect of oil pollution in coastal waters is the?

destruction of marine life

desalination of the water

increase in the acidity of the water Azịza ziri ezi

detoxification of the water

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Environmental Pollution (JAMB)

Environmental Pollution

Lee Azịza

Ajụjụ 14 Ripọtì

Which of the following are produced when ammonium trioxonitrate (V) crystals are cautiously heated in a hard glass round bottomed flask?

N2O and steam Azịza ziri ezi

NO2 and ammonia

N2O2 and NO2

NO and NO2

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Acids, Bases And Salts (JAMB)

Acids, Bases And Salts

Lee Azịza

Ajụjụ 15 Ripọtì

SO3 is NOT directly dissolved in water in the preparation of H2SO4 by the contact process because?

the reaction between SO3 and water is violently exothermic Azịza ziri ezi

acid is usually added to water and never water to acid

SO3 does not dissolve in water readily

SO3 is an acid gas

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Acids, Bases And Salts (Ghana Only) (WAEC)

Acids, Bases And Salts (Ghana Only)

Lee Azịza

Ajụjụ 16 Ripọtì

The densities of two gases, X and Y, are 0.5 g dm-3 and 2.0 dm-3 respectively.

What is the rate of diffusion of X relative to Y?

0.1

0.5

2.0 Azịza ziri ezi

4.0

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Kinetic Theory Of Matter And Gas Laws (JAMB)

Lee Azịza

Ajụjụ 17 Ripọtì

A pure solid usually melts?

over a wide range of temperature

over a narrow range of temperature Azịza ziri ezi

at a lower temperature than the impure one

at the same temperature as the impure one

Akọwa Nkọwa

In general, a pure solid usually melts over a narrow range of temperature. This is because a pure solid has a well-defined melting point, which is the temperature at which the solid transitions into its liquid state. The melting point of a pure solid is determined by its chemical composition and the strength of the intermolecular forces between its molecules. Impurities in a solid can disrupt the intermolecular forces and change the melting point of the solid. This is why impure solids may melt over a wider range of temperature or at a lower temperature than the corresponding pure solid. Therefore, if we compare the melting behavior of a pure solid and an impure solid, we can expect the pure solid to have a well-defined melting point and melt over a narrow range of temperature, while the impure solid may melt over a wider range of temperature or at a lower temperature.

Gụọ akwụkwọ nkuzi na Solubility (JAMB)

Solubility

Lee Azịza

Ajụjụ 18 Ripọtì

20 cm3 of a 2.0 M solution of ethanoic acid was added to excess of 0.05 M sodium hydroxide. The mass of the salt produced is?(Na = 23, C = 12, O = 16, H = 1)

2.50 g

2.73 g

3.28 g Azịza ziri ezi

4.54 g

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Kinetic Theory Of Matter And Gas Laws (JAMB)

Gụọ akwụkwọ nkuzi na Stoichiometry And Chemical Reactions (WAEC)

Stoichiometry And Chemical Reactions

Lee Azịza

Ajụjụ 19 Ripọtì

In an electrolytic set-up to protect iron from corrosion, the iron is?

made cathode

made anode

used with a metal of lower electropositive potential

initially coated with tin Azịza ziri ezi

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Electrolysis (JAMB)

Electrolysis

Lee Azịza

Ajụjụ 20 Ripọtì

What volume of oxygen measured at s.t.p would be liberated on electrolysis by 9650 coulombs of electricity?

(Molar volume of gas = 22.4 dm3, F = 96,500 C mol-)

22.4 dm3

11.2 dm3

1.12 dm3

0.560 dm3 Azịza ziri ezi

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Electrolysis (JAMB)

Electrolysis

Lee Azịza

Ajụjụ 21 Ripọtì

An anhydride is an oxide of non-mental?

which will not dissolve in water

whose solution in water has a pH greater than 7

whose solution in water has a pH less than 7 Azịza ziri ezi

whose solution in water has a pH of 7

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Periodic Chemistry (Ghana Only) (WAEC)

Periodic Chemistry (Ghana Only)

Lee Azịza

Ajụjụ 22 Ripọtì

The diagram above represents an atom of

magnesium Azịza ziri ezi

helium

chlorine

neon

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Structure Of The Atom (Ghana Only) (WAEC)

Gụọ akwụkwọ nkuzi na Atomic Structure And Bonding (JAMB)

Gụọ akwụkwọ nkuzi na Periodic Chemistry (Ghana Only) (WAEC)

Structure Of The Atom (Ghana Only)

Periodic Chemistry (Ghana Only)

Lee Azịza

Ajụjụ 23 Ripọtì

Which of the following is TRUE of Le Chatelier's Principle for an exothermic reaction?

Increase in temperature will cause an increase in the equilibrium constant

Increase in temperature will cause a decrease in the equilibrium constant Azịza ziri ezi

Addition of a catalyst will cause an increase in the equilibrium constant

Addition of a catalyst will cause a decrease in the equilibrium constant

Akọwa Nkọwa

Le Chatelier's Principle states that if a system at equilibrium is subjected to a change in temperature, pressure, or concentration of reactants or products, then the equilibrium shifts in the direction that tends to undo the effect of the change. For an exothermic reaction, increasing the temperature will cause a shift in the equilibrium towards the reactants, in order to reduce the effect of the added heat. This means that the equilibrium constant will decrease since it is a ratio of the concentrations of products to reactants at equilibrium. Therefore, the correct answer is "Increase in temperature will cause a decrease in the equilibrium constant." The addition of a catalyst will not affect the position of the equilibrium, but it will increase the rate at which the reaction reaches equilibrium. Therefore, the statement "Addition of a catalyst will cause an increase in the equilibrium constant" is false.

Gụọ akwụkwọ nkuzi na Kinetic Theory Of Matter And Gas Laws (JAMB)

Lee Azịza

Ajụjụ 24 Ripọtì

The IUPAC name of the compound above is

2,2-dimethyl but -1-yne

2,2-dmethyl but -1-ene

3,3-dimethyl but -1-ene Azịza ziri ezi

3,3-dimethyl but-1-yne

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

Lee Azịza

Ajụjụ 25 Ripọtì

Which of these metals CANNOT replace hydrogen from alkaline solutions?

Alulinium

Zinc

Tin

Iron Azịza ziri ezi

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Metals And Their Compounds (JAMB)

Metals And Their Compounds

Lee Azịza

Ajụjụ 26 Ripọtì

When sodium ethanoate is treated with a few drops of concentrated tetraoxosulphate(vi)acid. one of the products is

CH3COOH Azịza ziri ezi

CH3COOCH3

CH3COOC2H5

C2H5COOCH3

Akọwa Nkọwa

When sodium ethanoate (also known as sodium acetate) is treated with concentrated tetraoxosulphate (VI) acid (also known as sulfuric acid), one of the products formed is ethanoic acid (CH3COOH). This is due to the fact that the sulfuric acid protonates the acetate ion in the sodium ethanoate solution, leading to the formation of ethanoic acid and sodium sulfate as the other product. Therefore, the correct option is: CH3COOH.

Gụọ akwụkwọ nkuzi na Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

Lee Azịza

Ajụjụ 27 Ripọtì

A few drops of concentrated PCI are added to about 10cm3 of a solution of pH 3.4. The pH of the resulting mixtures is?

less than 3.4

greater than 3.4

unaltered Azịza ziri ezi

the same as that of pure water

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Acids, Bases And Salts (JAMB)

Acids, Bases And Salts

Lee Azịza

Ajụjụ 28 Ripọtì

Use the diagram above to answer this question.

The reaction taking place in the flask above is known as

hydrolysis

double decomposition

dehydration Azịza ziri ezi

pyrolysis

Akọwa Nkọwa

The reaction taking place in the flask above is dehydration. Dehydration is a chemical reaction that involves the removal of water from a molecule or compound. In the diagram, there is a reactant (the pink molecule) that loses a water molecule (H2O) and forms a new compound (the blue molecule). This process is known as dehydration, and it is represented by the removal of water (H2O) from the pink molecule, leaving behind a double bond (represented by the black line) between the two carbon atoms.

Gụọ akwụkwọ nkuzi na Acids, Bases And Salts (JAMB)

Acids, Bases And Salts

Lee Azịza

Ajụjụ 29 Ripọtì

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

4 Azịza ziri ezi

Akọwa Nkọwa

The atomic number of an element tells us the number of protons in its nucleus, which is also equal to the number of electrons in the neutral atom. The element with atomic number 14 is Silicon (Si). To determine the number of electrons in the valence shell, we need to look at the electron configuration of Silicon. The electron configuration of Silicon is 1s2 2s2 2p6 3s2 3p2. The valence shell of an atom is the outermost shell containing electrons, and in the case of Silicon, this is the 3rd shell (3s2 3p2). The number of electrons in the valence shell of Silicon is equal to the sum of the electrons in the s and p orbitals of that shell, which is 2 + 2 = 4. Therefore, the correct answer is 4, which means that Silicon has 4 valence electrons.

Gụọ akwụkwọ nkuzi na Atomic Structure And Bonding (JAMB)

Lee Azịza

Ajụjụ 30 Ripọtì

Crude copper could be purified by the electrolysis of concentrated copper (II) chloride if the crude copper is?

made both the anode and the cathode

made the cathode

made the anode Azịza ziri ezi

dissolved in the solution

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Electrolysis (JAMB)

Electrolysis

Lee Azịza

Ajụjụ 31 Ripọtì

Which of the following compounds is NOT an isomers of 2,2 dimethylbutane?

2-methylbutane Azịza ziri ezi

3-methylpentane

2,3-dimethylbutane

2-methylpentane

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

Lee Azịza

Ajụjụ 32 Ripọtì

The ∆H for the reaction represented by the energy profile above is

-100 kJ mol--1

+ 100 kJ mol-1

+50 kJ mol-1

-50 kJ mol-1 Azịza ziri ezi

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Energy Changes (JAMB)

Gụọ akwụkwọ nkuzi na Energy And Energy Changes (WAEC)

Energy Changes

Energy And Energy Changes

Lee Azịza

Ajụjụ 33 Ripọtì

Which of these solutions will give a white precipitate with a solution of barium chloride acidified with hydrochloric acid?

Sodium trioxocarbonate (IV) Azịza ziri ezi

Sodium tetraoxosulphate (IV)

Sodium trioxosulphate (IV)

Sodium sulphide

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Acids, Bases And Salts (Ghana Only) (WAEC)

Acids, Bases And Salts (Ghana Only)

Lee Azịza

Ajụjụ 34 Ripọtì

The set-up above would be useful for determining the amount of

oxygen in air

water vapour in air Azịza ziri ezi

CO2 in air

arygen in air

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Air (JAMB)

Air

Lee Azịza

Ajụjụ 35 Ripọtì

In the diagram above, R is a mixture of

potassium tetraxochlorate (VII) and concentrated H2SO4

potassium trioxochlorate (V) and concentrated H2SO4

potassium tetratoxomanganate (VII) and concentrated HCI

manganes (IV) oxide and concentrated HCI Azịza ziri ezi

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Acids, Bases And Salts (JAMB)

Acids, Bases And Salts

Lee Azịza

Ajụjụ 36 Ripọtì

When sodium is added to ethanol, the products are?

sodium hydroxide and water

sodium hydroxide and hydrogen

sodium ethoxide and water

sodium ethoxide and hydrogen Azịza ziri ezi

Akọwa Nkọwa

When sodium is added to ethanol, the products are sodium ethoxide (NaC2H5O) and hydrogen gas (H2). This is because sodium is a highly reactive metal that reacts with ethanol to displace the hydrogen atom attached to the carbon atom in the -OH group. As a result, the hydrogen atom combines with another hydrogen atom to form hydrogen gas, while the remaining ethoxide ion combines with the sodium cation to form sodium ethoxide. Therefore, the correct option is: sodium ethoxide and hydrogen gas.

Gụọ akwụkwọ nkuzi na Electrolysis (JAMB)

Gụọ akwụkwọ nkuzi na Acids, Bases And Salts (JAMB)

Electrolysis

Acids, Bases And Salts

Lee Azịza

Ajụjụ 37 Ripọtì

Which of the following physical properties decreases down a group in the periodic table?

Atomic radius

Ionic radius Azịza ziri ezi

Electropositivity

Electronegativity

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Atomic Structure And Bonding (JAMB)

Lee Azịza

Ajụjụ 38 Ripọtì

At the same temperature and pressure, 50 cm3 of nitrogen gas contains the same number of molecules as?

25 cm3 of methane

40 cm3 of hydrogen

50 cm3 of ammonia Azịza ziri ezi

100 cm3 of chlorine

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Kinetic Theory Of Matter And Gas Laws (JAMB)

Lee Azịza

Ajụjụ 39 Ripọtì

The general formula of alkanoates is?

RCHO

R2CO Azịza ziri ezi

RCOOH

RCOOR

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Chemistry Of Carbon Compounds (Ghana Only) (WAEC)

Gụọ akwụkwọ nkuzi na Periodic Chemistry (Ghana Only) (WAEC)

Chemistry Of Carbon Compounds (Ghana Only)

Periodic Chemistry (Ghana Only)

Lee Azịza

Ajụjụ 40 Ripọtì

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

298 K

546 K

819 K

1092 K Azịza ziri ezi

Akọwa Nkọwa

According to the Ideal Gas Law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles of gas, R is the gas constant, and T is the temperature in Kelvin. If we want to double both the volume and pressure of the gas while keeping the number of moles constant, then we can use the combined gas law, which states: (P1V1)/T1 = (P2V2)/T2 where P1 and V1 are the initial pressure and volume, and P2 and V2 are the final pressure and volume. Since we want to double both the pressure and volume, we can set: P2 = 2P1 V2 = 2V1 Substituting these values into the combined gas law, we get: (P1*2V1)/T1 = (2P1*2V1)/T2 Simplifying, we get: T2 = T1*4 So, the temperature must be quadrupled in order to double both the pressure and volume. Since the initial temperature is 273 K, we can multiply it by 4 to get the final temperature: T2 = 273 K * 4 = 1092 K Therefore, the answer is 1092 K.

Gụọ akwụkwọ nkuzi na Kinetic Theory Of Matter And Gas Laws (JAMB)

Lee Azịza

Ajụjụ 41 Ripọtì

In the diagram above the activation energy is represented by

y - x Azịza ziri ezi

x - z

Akọwa Nkọwa

In the diagram, the activation energy is represented by the vertical distance between the reactants (energy level x) and the maximum point in the curve (energy level y). Therefore, the answer is "y - x".

Gụọ akwụkwọ nkuzi na Kinetic Theory Of Matter And Gas Laws (JAMB)

Lee Azịza

Ajụjụ 42 Ripọtì

The solubility, in moles per dm3 of 20.2 g of potassium trioxonitrate (V) dissolve in 100 g of the resulting mixture is?(K = 39, O = 16, N =14).

0.10

0.20

1.00

2.00 Azịza ziri ezi

Akọwa Nkọwa

The first step to solve the problem is to calculate the molar mass of potassium trioxonitrate (V), which is given by: KNO₃ = (1 x 39) + (1 x 14) + (3 x 16) = 101 g/mol Next, we need to calculate the number of moles of potassium trioxonitrate (V) that are present in 20.2 g: moles of KNO₃ = mass / molar mass = 20.2 / 101 = 0.2 mol Now, we need to calculate the total mass of the resulting mixture. This is given by: mass of resulting mixture = mass of KNO₃ + mass of water = 20.2 + 100 = 120.2 g Finally, we can calculate the solubility of potassium trioxonitrate (V) in moles per dm³ by dividing the number of moles of KNO₃ by the volume of the resulting mixture in dm³. The volume of the resulting mixture is equal to 0.1 dm³ (since 100 g of water is equal to 0.1 dm³): solubility = moles / volume = 0.2 / 0.1 = 2.0 Therefore, the solubility of potassium trioxonitrate (V) in moles per dm³ is 2.0 mol/dm³, which corresponds to option (D).

Gụọ akwụkwọ nkuzi na Oxidation And Reduction (JAMB)

Oxidation And Reduction

Lee Azịza

Ajụjụ 43 Ripọtì

\( \mathrm{MnO_4(aq) + 8H + 5Fe^{2+} \rightarrow Mn^{2+}(aq) + 5Fe^{3+}(aq) + H_2O} \). The oxidation number of maganese in the above reaction changed from

+8 to +2 Azịza ziri ezi

+6 to +2

+5 to +2

+4 to +2

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Kinetic Theory Of Matter And Gas Laws (JAMB)

Gụọ akwụkwọ nkuzi na Separation Of Mixtures And Purification Of Chemical Substances (JAMB)

Separation Of Mixtures And Purification Of Chemical Substances

Lee Azịza

Ajụjụ 44 Ripọtì

Which of the following is the correct order of decreasing activity of the metals Fe, Ca, Al and Na?

Fe> Ca> Al> Na

Na> Ca> Al> Fe Azịza ziri ezi

Al> Fe> Na> Ca

Ca> Na> Fe>, Al

Akọwa Nkọwa

The reactivity of metals is related to their tendency to lose electrons and form positive ions. Metals that lose electrons easily are more reactive, while metals that don't lose electrons easily are less reactive. The order of decreasing activity of the metals Fe, Ca, Al, and Na can be determined by their position in the reactivity series. In the reactivity series, metals are listed in order of decreasing reactivity. The most reactive metals are at the top, and the least reactive metals are at the bottom. The reactivity series is based on how readily the metals react with water and dilute acids. The correct order of decreasing activity of the metals Fe, Ca, Al, and Na is: Na > Ca > Al > Fe This is because Na is the most reactive metal, followed by Ca, Al, and Fe. Therefore, is the correct answer. Na (s) + H2O (l) -> NaOH (aq) + 1/2H2 (g) Ca (s) + H2O (l) -> Ca(OH)2 (aq) + H2 (g) Al (s) + 3H2O (l) -> Al(OH)3 (aq) + 3/2H2 (g) Fe (s) + H2O (l) -> Fe(OH)2 (s) + H2 (g)

Gụọ akwụkwọ nkuzi na Metals And Their Compounds (JAMB)

Metals And Their Compounds

Lee Azịza

Ajụjụ 45 Ripọtì

From the above diagram, the caustic soda in the conical flask serves to

dry ethene gas

remove carbon (iv) oxides from ethene

remove carbon (ii) oxide from ethene Azịza ziri ezi

remove sulphur (iv) oxide from ethene

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Acids, Bases And Salts (JAMB)

Acids, Bases And Salts

Lee Azịza

Ajụjụ 46 Ripọtì

Which of the following atoms represents deuterium?

No protons = 1, No of neutrons = 0, No of electrons = 0

No protons = 1, No of neutrons = 0, No of electrons = 1

No protons = 1, No of neutrons = 1, No of electrons = 1 Azịza ziri ezi

No protons = 1, No of neutrons = 2, No of electrons = 1

Akọwa Nkọwa

Deuterium is an isotope of hydrogen which has one proton and one neutron in its nucleus. Therefore, the correct answer would be the option that has one proton and one neutron, and one electron to balance the charge of the nucleus. The only option that satisfies this requirement is "No protons = 1, No of neutrons = 1, No of electrons = 1". So, the answer is.

Gụọ akwụkwọ nkuzi na Structure Of The Atom (WAEC)

Structure Of The Atom

Lee Azịza

Ajụjụ 47 Ripọtì

Which of the following is NOT true of metals?

They are good conductors of electricity

They ionize by electron loss

Their oxides are acidic Azịza ziri ezi

They have high melting points

Akọwa Nkọwa

The statement that is NOT true of metals is: "Their oxides are acidic". Metals are elements that tend to have certain characteristics such as good conductivity of heat and electricity, high melting points, and the ability to lose electrons to form positively charged ions or cations. When a metal reacts with oxygen, it forms metal oxide, which may be either basic or amphoteric, but not acidic. Basic oxides react with acids to form salts and water, while amphoteric oxides can react as either an acid or a base. Therefore, their oxides are not acidic, but either basic or amphoteric in nature.

Gụọ akwụkwọ nkuzi na Metals And Their Compounds (JAMB)

Metals And Their Compounds

Lee Azịza

Ajụjụ 48 Ripọtì

Element X, Y and Z belong to a groups I, V and VII respectively. Which of the following is TRUE about the bond types of XZ and YZ3?

Both are electrovalent

Both are covalent

XZ is electrovalent and YZ3 is covalent Azịza ziri ezi

XZ is covalent and YZ3 is electrovalent

Akọwa Nkọwa

The bond types of XZ and YZ can be determined based on the electronic configuration of the elements. Group I elements, such as X, have one valence electron, while Group V elements, such as Y, have five valence electrons. Group VII elements, such as Z, have seven valence electrons. To achieve stability, Group I elements tend to lose one electron to achieve a stable noble gas configuration, while Group V elements tend to gain three electrons to achieve a stable noble gas configuration. Group VII elements tend to gain one electron to achieve a stable noble gas configuration. Therefore, in the case of XZ, element X will lose one electron to element Z to form an electrovalent or ionic bond. In the case of YZ, element Y will share three electrons with element Z to form a covalent bond. Thus, the correct option is: XZ is electrovalent and YZ is covalent.

Gụọ akwụkwọ nkuzi na Chemical Bonds (Ghana Only) (WAEC)

Chemical Bonds (Ghana Only)

Lee Azịza

Ajụjụ 49 Ripọtì

A mixture of sand, ammonium chloride and sodium chloride is best separated by?

sublimation followed by addition of water and filteration Azịza ziri ezi

sublimation followed by addition of water and evaporation

addition of water followed by filtration and sublimation

addition of water followed by crystallization and sublimation

Akọwa Nkọwa

The best method to separate the mixture of sand, ammonium chloride, and sodium chloride is "sublimation followed by addition of water and filtration". The mixture contains two sublimating components, sand and ammonium chloride, and one non-sublimating component, sodium chloride. Therefore, sublimation can be used to separate the mixture into two components. By heating the mixture, ammonium chloride sublimes, and can be collected on a cool surface as solid. The remaining mixture will contain sand and sodium chloride. Next, water can be added to dissolve the sodium chloride, leaving the sand as a residue. The solution containing sodium chloride can then be filtered to remove any insoluble impurities, leaving behind a clear solution of sodium chloride. Therefore, the correct option for separating the given mixture is "sublimation followed by addition of water and filtration".

Gụọ akwụkwọ nkuzi na Separation Of Mixtures And Purification Of Chemical Substances (JAMB)

Separation Of Mixtures And Purification Of Chemical Substances

Lee Azịza

Ajụjụ 50 Ripọtì

One mole of a hydrocarbon contains 48 g of carbon. If it vapour density is 28, the hydrocarbon is?

an alkane

an alkene Azịza ziri ezi

an alkyne

aromatic (C = 12, H = 1)

Akọwa Nkọwa

Gụọ akwụkwọ nkuzi na Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)