Cambridge IGCSE Chemistry - 0620 - Core Paper 1 2012 Winter Zone 3

‘Particles moving very slowly from an area of high concentration to an area of low concentration.’
Which process is being described above?

Solid W melts at exactly 54°C and boils at exactly 302°C.
Solid X, when dissolved in water and examined using paper chromatography, shows a blue colour and a red colour.
Which row is correct?
[Table_1]

Part of the instructions in an experiment reads as follows.
Quickly add 50 $\text{cm}^3$ of acid.
What is the best piece of apparatus to use?

The nucleon number of an isotope of rubidium is 85.
How many protons, neutrons and electrons are present in an atom of this isotope?
[Table_1]

Which row gives the number of electrons in the outer electron shell of fluorine and of neon?
[Table_1]

In the molecules $CH_4$, $HCl$ and $H_2O$, which atoms use all of their outer shell electrons in bonding?

The table shows the electronic structures of four atoms.

[Table_1]

Which two atoms combine to form an ionic compound?

A compound has the formula $\text{CH}_3\text{CO}_2\text{H}$.
How should the relative molecular mass, $M_r$, of this compound be calculated?

In separate experiments, electricity was passed through concentrated aqueous sodium chloride and molten lead bromide.
What would happen in both experiments?

The diagram shows an electrolysis experiment using metals X and Y as electrodes.
[Image_1: Diagram of electrolysis setup with electrodes X and Y]
One of the metals becomes coated with copper.
Which metal becomes coated and which aqueous solution is used?

A diagram for the energy change during an exothermic reaction is shown.

For which reactions would this be an appropriate diagram?
1 $\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}$
2 $2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}$
3 $\text{C} + \text{O}_2 \rightarrow \text{CO}_2$

The diagram shows a match.
By striking the match, a chemical reaction takes place.
Which statements about the chemical reaction are correct?

Solid copper(II) sulfate can exist in two different forms, anhydrous and hydrated. One of these forms is blue and the other is white.
The change between these two forms is reversible.
blue form ⇌ white form
Which is the blue form and how is the change from the blue form to the white form brought about?

[Table_1]

Which statement describes what happens in the reaction shown?
$$2\text{Mg} + \text{CO}_2 \rightarrow 2\text{MgO} + \text{C}$$

Which change does not increase the speed of reaction between zinc and hydrochloric acid?

Salts X and Y are separately dissolved in water.
Samples of the solutions obtained are separately tested with dilute hydrochloric acid and with aqueous sodium hydroxide.
In two of the tests, a gaseous product is formed. No precipitate is formed in any of the tests.
What are salts X and Y?
[Table_1]

Some reactions involving sodium are shown.
Which reaction does not involve the formation of a base?

Barium hydroxide is an alkali. It reacts with hydrochloric acid.
How does the pH of the hydrochloric acid change as an excess of aqueous barium hydroxide is added?

A compound is a salt if it

The diagram shows an outline of the Periodic Table.
Which ionic compound could be formed?

Element X is in Group VII of the Periodic Table. It reacts with aqueous potassium bromide as shown.

$X_2 + 2KBr \rightarrow 2KX + Br_2$

Which statements about X are correct?

[Table_1]

The table gives information about four elements.
Which element is a transition metal?
[Table_1]

Why are weather balloons filled with helium rather than hydrogen?

The three statements below about aluminium are all correct.
1. Aluminium has an oxide ore.
2. Aluminium is extracted from its ore by electrolysis.
3. Aluminium is used to make cooking utensils.
In which of these statements can ‘aluminium’ be replaced by ‘iron’ and still be correct?
[Table_1]

Statement 1: An aluminium alloy containing a small amount of copper is stronger than pure aluminium.
Statement 2: Alloys are made by mixing molten metals together and allowing them to cool.
Which of the following is true?

Iron is extracted from its ore in a Blast Furnace.
Hematite, coke, limestone and hot air are added to the furnace.
Which explanation is not correct?

How does the reactivity of potassium compare with that of sodium and how does the reactivity of calcium compare with that of magnesium?
[Table with reactivity comparisons]

Untreated water can spread diseases such as cholera.
What can be added to drinking water to reduce the spread of such diseases?

Statement 1: The burning of fossil fuels containing sulfur is a cause of 'acid rain'.
Statement 2: Acid rain contains sulfur dioxide which is formed when sulfur compounds burn in the air.
Which of the following is true?

Argon is a noble gas used to fill light bulbs.
What is the approximate percentage of argon in air?

The experiment shown was set up to investigate the rusting of iron.
Rusting occurs in this experiment because of the presence of

What are X and Y in the reaction shown?
ammonium chloride + solution X \rightarrow alkaline gas Y
[Table_1]

Which process does not produce carbon dioxide?

Two industrial processes that involve heating are:
• extracting iron from its ore using a blast furnace,
• making lime.
In which of these processes is calcium carbonate used?
[Table_1]

Which structure shows a carboxylic acid?

Which method is used to obtain petrol from petroleum?

Which group of compounds is part of a homologous series?

Bitumen is a substance obtained from the fractional distillation of petroleum.
Which row describes its boiling point and the size of its molecules?
[Table_1]

A hydrocarbon A is cracked to make B and hydrogen.
Compound C is formed by the addition polymerisation of B.
To which homologous series do A, B and C belong?
[Table_1]

Which statement about ethanol is \textbf{not} correct?