Oct/Nov 2019

The diagram depicts a cup of hot tea. Which row compares the water particles in the air above the cup with the water particles in the cup?

Solids, liquids and gases

In the electrolysis of concentrated hydrochloric acid, gases form at both electrodes. Which statement gives the test result for the gas gathered at the negative electrode?

Electrolysis

Which statements about endothermic reactions are correct?

Exothermic and endothermic reactions

Equations showing the preparation of anhydrous cobalt(II) chloride and anhydrous copper(II) sulfate are given below. $\text{CoCl}_2 \cdot 6\text{H}_2\text{O} \rightarrow \text{CoCl}_2 + 6\text{H}_2\text{O}$ $\text{CuSO}_4 \cdot 5\text{H}_2\text{O} \rightarrow \text{CuSO}_4 + 5\text{H}_2\text{O}$ Which statement about these reactions is not correct?

Physical and chemical changes

An investigation method for finding the rate of reaction of calcium carbonate with dilute hydrochloric acid under different conditions is shown. • Pour $50\text{ cm}^3$ of dilute hydrochloric acid into a conical flask. • Add a measured volume of water to the conical flask. • Warm the conical flask to the necessary temperature. • Put $1.0\text{ g}$ of calcium carbonate into the conical flask. • Record the time needed for the reaction to end. Which volume of water and which temperature results in the shortest time for the reaction to complete?

Rate of reaction

Which one is a chemical change?

Physical and chemical changes

Mercury(II) oxide, $\text{HgO}$, breaks down when it is heated. The equation is given below. $2\text{HgO} \rightarrow 2\text{Hg} + \text{O}_2$ Why can this be described as a reduction reaction?

Redox

Carbonic acid is a weak acid produced when carbon dioxide dissolves in water. What pH does the solution have?

The characteristic properties of acids and bases

Solid X is examined using the method shown. Reaction with dilute aqueous sodium hydroxide: no reaction occurs. Flame test: a red flame is observed. Reaction with dilute hydrochloric acid: a gas is produced that turns limewater milky. What substance is X?

Identification of ions and gases

Which oxide is basic in nature?

Oxides

A procedure for making copper(II) sulfate crystals is illustrated.

Preparation of salts

A student is required to determine the time taken for $0.4\,\text{g}$ of magnesium carbonate to react completely with $25.0\,\text{cm}^3$ of dilute hydrochloric acid. Which pieces of apparatus are needed by the student?

Rate of reaction

Which group of elements illustrates the shift from metallic to non-metallic character along a period of the Periodic Table?

Arrangement of elements

Which pair of elements reacts with each other most violently?

Group I properties

Which of the following is not usually a characteristic of a transition element?

Transition elements

A section of the Periodic Table is shown. Which element is used to create an inert atmosphere?

Noble gases

Several characteristics of substance X are given below. • It conducts electricity when molten. • Its melting point is high. • It reacts with oxygen, and the oxide dissolves in water to form a solution with $\text{pH} = 11$. Which substance is X?

Ions and ionic bonds

Four different metals are each reacted with the same volume of dilute hydrochloric acid. The outcomes of the reactions are shown below. metal / rate of effervescence: calcium - very high copper - none iron - low magnesium - high What is the sequence of reactivity for these four metals, beginning with the most reactive?

Reactivity series

Iron is obtained from its ore in a blast furnace. The equations for four separate reactions are given below. 1 $4\text{Fe} + 3\text{CO}_2 \rightarrow 2\text{Fe}_2\text{O}_3 + 3\text{C}$ 2 $\text{CO}_2 \rightarrow \text{C} + \text{O}_2$ 3 $\text{CO}_2 + \text{C} \rightarrow 2\text{CO}$ 4 $\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2$ Which equations show reactions that take place in the blast furnace?

Extraction of metals

Which of the statements is correct?

Elements, compounds and mixtures

River water can include soluble impurities, insoluble impurities, and bacteria. To make river water safe for drinking, it is filtered and then chlorinated. Which statement is correct?

Water

Nitrogen, oxygen and small quantities of other gases make up clean, dry air. The table does not include the noble gases. Which row gives the composition of clean, dry air?

Elements, compounds and mixtures

A fractionating column is used to separate the hydrocarbon fractions in petroleum by fractional distillation. Which row describes the properties of the fractions that condense near the top of the fractionating column?

Fuels

The apparatus illustrated is assembled and then left for one week. Which diagram indicates the water level at the end of the week?

Diffusion

Farmers apply calcium oxide (lime) and ammonium salts to their fields. These compounds are not put on at the same time, since they would react together. Which gas is formed in this reaction?

The characteristic properties of acids and bases

Which piece of information about carbon dioxide and methane is correct?

Simple molecules and covalent bonds

Which of the following is not a use of sulfur dioxide?

Oxides

Which method is used to produce lime from limestone?

Physical and chemical changes

Fractional distillation is used to separate petroleum. Which statement about the fractions formed is correct?

Fuels

Which compounds show similar chemical properties?

Formulae, functional groups and terminology

Which statement about an ethane molecule is correct?

Simple molecules and covalent bonds

What products are produced when an alkane undergoes cracking?

Alkanes

Which of the following statements about aqueous ethanoic acid are correct?

The characteristic properties of acids and bases

The following details are given about solid silver chloride and solid sodium chloride. • Silver chloride and sodium chloride do not dissolve in kerosene. • Silver chloride is insoluble in water, whereas sodium chloride is soluble in water. • The boiling point of silver chloride is $1547\,^{\circ}\text{C}$ and the boiling point of sodium chloride is $1413\,^{\circ}\text{C}$. What processes are used to separate a mixture of solid silver chloride and solid sodium chloride?

Separation and purification

The diagram illustrates the structure of a monomer and the polymer formed from it. What are the monomer and polymer?

Polymers

A covalent molecule M has four pairs of electrons shared between atoms. What is M?

Simple molecules and covalent bonds

An isotope of chromium is written as $^{52}_{24}\text{Cr}$. Which of the following statements about an atom of this chromium isotope is correct?

Isotopes

Substances P and Q each conduct electricity. P is a mixture containing two different atom types. Q consists of only one atom type. Which row best describes P and Q?

Elements, compounds and mixtures

Graphite is one allotrope of carbon. Why is graphite suitable for use as a lubricant?

Giant covalent structures

The diagram shows the structure of a molecule. What is the formula of this molecule?

Formulae

The diagram depicts a cup of hot tea. Which row compares the water particles in the air above the cup with the water particles in the cup?

Solids, liquids and gases

The setup for electrolysis is shown below. Which statement is correct?

Electrolysis

The temperature of the water in two beakers, X and Y, is recorded as $21.5\,^{\circ}\text{C}$. $5\,\text{g}$ of sodium chloride is added to the water in beaker X. The temperature then falls to $18.0\,^{\circ}\text{C}$. $5\,\text{g}$ of calcium oxide is added to the water in beaker Y. The temperature then rises to $29.4\,^{\circ}\text{C}$. What kinds of process are taking place in beakers X and Y?

Exothermic and endothermic reactions

Which reaction leads to a white-coloured substance?

Identification of ions and gases

Four students gather the gas formed when calcium carbonate reacts with dilute hydrochloric acid. Each student measures the time required to collect a given volume of gas. Which results indicate the greatest average rate of reaction?

Rate of reaction

Which row correctly identifies a chemical change and a physical change?

Physical and chemical changes

If magnesium is heated with zinc oxide, a reaction takes place. The equation is shown. $\text{Mg} + \text{ZnO} \rightarrow \text{MgO} + \text{Zn}$ Which substance undergoes oxidation?

Redox

Which option gives the properties of hydrochloric acid?

The characteristic properties of acids and bases

A sample of X is warmed with aqueous sodium hydroxide and small pieces of aluminium. A gas is given off that turns red litmus paper blue. Aqueous sodium hydroxide solution is then added to a second sample of X. A pale green precipitate is seen. What is X?

Identification of ions and gases

Which element is capable of forming an acidic oxide?

Oxides

The diagram below shows a procedure for preparing copper(II) sulfate crystals. 1. Put dilute sulfuric acid into a beaker. 2. Heat the acid. 3. Add copper(II) oxide until some is left over. 4. Filter the mixture. 5. Evaporate the filtrate until crystals begin to appear. 6. Allow the filtrate to cool. What are the purposes of step 3 and step 4?

Preparation of salts

A student wants to find the time needed for $0.4\,\text{g}$ of magnesium carbonate to react fully with $25.0\,\text{cm}^3$ of dilute hydrochloric acid. Which apparatus are required by the student?

Rate of reaction

Which statements describe the changes that take place from left to right across a period of the Periodic Table?

Arrangement of elements

Which pair of elements reacts with the greatest violence?

Group I properties

Which characteristic is typical of transition elements?

Transition elements

Helium belongs to the noble gases. Which of the following statements about helium is correct?

Noble gases

A few characteristics of substance X are given below. • It allows electricity to pass through it when molten. • Its melting point is high. • It reacts in oxygen, and the oxide formed dissolves in water to produce a solution with $\text{pH} = 11$. What is X?

Ions and ionic bonds

Four unidentified metals, Q, R, S and T, are reacted with water, steam and dilute hydrochloric acid. The outcomes are displayed in the table. Which statements are correct?

Reactivity series

What substance is added to molten iron in order to produce steel?

Alloys and their properties

Which row shows how aluminium, copper and mild steel are used?

Uses of metals

Soluble impurities, insoluble impurities and bacteria are present in river water. It is made fit to drink by filtration and chlorination. Which statement is correct?

Water

Clean, dry air is made up of nitrogen, oxygen and only tiny quantities of other gases. The noble gases are not included in the table. Which row gives the composition of clean, dry air?

Elements, compounds and mixtures

Petroleum is a mixture. By which method is petroleum separated?

Separation and purification

The apparatus illustrated is assembled and then left for a week. Which diagram shows the water level at the end of the week?

Diffusion

Farmers spread calcium oxide (lime) and ammonium salts onto their fields. These compounds are not applied at the same time because they react with one another. Which gas is formed in this reaction?

The characteristic properties of acids and bases

Which statement about carbon dioxide and methane is correct?

Air quality and climate

Which statement concerning the uses of sulfur dioxide is incorrect?

Oxides

Which one of the following statements about limestone and lime is correct?

Oxides

Several fractions separated from petroleum are shown. Which of the rows are correct?

Fuels

The structures for three compounds are displayed. Which statement accounts for why these three compounds have similar chemical properties?

Formulae, functional groups and terminology

Which of the following statements about ethane is correct?

Alkanes

What products are produced when an alkane is cracked?

Alkanes

Which of the following statements about an aqueous solution of ethanoic acid is correct?

The characteristic properties of acids and bases

Magnesium hydroxide may be produced from sea water, as illustrated. Which separation process is used to remove solid magnesium hydroxide from the mixture in the separation stage?

Separation and purification

The diagram displays the arrangement of a monomer and the polymer formed from that monomer. What are the monomer and polymer?

Polymers

How many electrons are present in a single molecule of ammonia, $\text{NH}_3$?

Atomic structure and the Periodic Table

An isotope of lithium is shown by the symbol $^7_3\text{Li}$. How are the electrons arranged in one atom of this lithium isotope?

Atomic structure and the Periodic Table

Which of the following statements about an alloy is correct?

Alloys and their properties

Graphite is a type of carbon. Why is graphite suitable for use as a lubricant?

Giant covalent structures

When magnesium reacts with oxygen, magnesium oxide is produced. The reaction is represented by the equation below. $2\text{Mg} + \text{O}_2 \rightarrow 2\text{MgO}$ What mass of magnesium oxide will be produced when $48\,\text{g}$ of magnesium is burned?

The mole and the Avogadro constant

The diagram shows a cup of hot tea. Which row describes how the water particles in the air above the cup compare with the water particles in the cup?

Solids, liquids and gases

Dilute sulfuric acid and lead(II) bromide are electrolysed separately. Which of the following statements are correct?

Electrolysis

A reaction is represented by an energy level diagram. Which statement and explanation about this reaction are correct?

Exothermic and endothermic reactions

When heated, hydrated cobalt(II) chloride breaks down. $\text{CoCl}_2\cdot6\text{H}_2\text{O} \rightarrow \text{CoCl}_2 + 6\text{H}_2\text{O}$ Which of these statements about this reaction are correct?

Physical and chemical changes

For experiment 1, small pieces of limestone are placed into dilute hydrochloric acid at $40^\circ\text{C}$. The volume of carbon dioxide given off is measured at regular time intervals. The results are shown. Which changes produce the results shown in experiment 2?

Rate of reaction

A set of transformations involving sulfur is shown. $\text{S(s)} \xrightarrow{\text{change 1}} \text{S(l)} \xrightarrow{\text{change 2}} \text{SO}_2\text{(g)}$ Which row gives the correct description of the changes?

Physical and chemical changes

In which equation does the iron undergo oxidation?

Redox

Which of the following statements about dilute sulfuric acid are correct?

The characteristic properties of acids and bases

X is a white powder. The following tests are carried out on X: When a few drops of aqueous sodium hydroxide are added to a solution of X, no precipitate is observed. When X is heated with aqueous sodium hydroxide, no gas is produced. When X is placed in a flame, it gives a lilac colour. If acidified aqueous silver nitrate is added to a solution of X, a yellow precipitate is observed. What is X?

Identification of ions and gases

Which three oxides are classified as acidic?

Oxides

A procedure for producing copper(II) sulfate crystals is illustrated below. 1. Put dilute sulfuric acid into a beaker. 2. Heat the acid. 3. Continue adding copper(II) oxide until some remains unreacted in excess. 4. Filter the mixture. 5. Evaporate the filtrate until crystals begin to appear. 6. Allow the filtrate to cool. What are the purposes of step 3 and step 4?

Preparation of salts

A student is required to find the time taken for 0.4 g of magnesium carbonate to react fully with $25.0\ \text{cm}^3$ of dilute hydrochloric acid. Which apparatus items are needed by the student?

Experimental design

Which element in Period 3 of the Periodic Table shows the greatest metallic character?

Arrangement of elements

Which pair of elements reacts with the greatest violence?

Reactivity series

Which statement does not give a description of a transition element?

Transition elements

Which statement gives a description of a gas that is in Group VIII of the Periodic Table?

Noble gases

Several properties of substance X are given below. It is an electrical conductor when molten. Its melting point is high. When it burns in oxygen, the oxide formed dissolves in water to produce a solution with pH $11$. What is X?

Ions and ionic bonds

A metal reacts strongly with water. Which statement about this metal is correct?

Group I properties

Iron is extracted from its ore in the blast furnace. Which raw material is not used in this process?

Extraction of metals

Which statement concerning metals and their uses is correct?

Uses of metals

River water contains soluble impurities, insoluble impurities, and bacteria. It is rendered safe for drinking by filtration and chlorination. Which statement is correct?

Water

Clean, dry air is made up of nitrogen, oxygen and trace quantities of other gases. The noble gases are not included in the table. Which row gives the composition of clean, dry air?

Elements, compounds and mixtures

Which technique is used to separate a mixture of the liquids shown below?

Separation and purification

The apparatus illustrated is arranged and then left for a week. Which diagram shows the water level at the end of the week?

Diffusion

Farmers spread calcium oxide (lime) and ammonium salts on their fields. These substances are not applied at the same time because they react with each other. Which gas is produced in this reaction?

The characteristic properties of acids and bases

Which statement about carbon dioxide and methane is correct?

Air quality and climate

What uses does sulfur dioxide have?

Oxides

What type of reaction takes place when lime is produced from limestone?

Physical and chemical changes

Which one of the statements is correct?

Elements, compounds and mixtures

The structures of four organic compounds, W, X, Y and Z, are shown. Which of these compounds belong to the same homologous series?

Formulae, functional groups and terminology

How many distinct types of bonds are found in ethanoic acid, $\text{CH}_3\text{COOH}$?

Simple molecules and covalent bonds

What products are produced when an alkane is cracked?

Alkanes

Which claim about aqueous ethanoic acid is correct?

The characteristic properties of acids and bases

A wax sample is heated. Melting starts at $45^\circ \text{C}$ and is complete at $49^\circ \text{C}$. A liquid sample is heated. Boiling starts at $141^\circ \text{C}$ and the temperature stays at $141^\circ \text{C}$ during boiling. Which conclusion can be drawn from these observations?

Solids, liquids and gases

The diagram displays the structure of a monomer and the polymer formed from it. What are the monomer and polymer?

Polymers

In which molecule do all the outer shell electrons take part in covalent bonding?

Simple molecules and covalent bonds

The numbers of protons, neutrons and electrons in atoms P, Q, R and S are given. Which of these atoms are isotopes of the same element?

Isotopes

What does the term alloy mean?

Alloys and their properties

Graphite is a form of carbon. What property allows graphite to be used as a lubricant?

Giant covalent structures

During the thermal decomposition of 12.5 g of limestone (impure calcium carbonate), 5 g of calcium oxide are obtained. What mass of calcium oxide would be obtained from the thermal decomposition of 30 g of limestone?

Relative masses of atoms and molecules