Theory

CH7 - REDOX REACTIONS

The reactions shown may occur in the air during a thunder storm.$$ \text{N}_2 + \text{O}_2 \rightarrow 2\text{NO} $$$$ 2\text{NO} + \text{O}_2 \righta...

2009 Summer

Theory

CH7 - REDOX REACTIONS

The reactions shown may occur in the air during a thunder storm.$$N_2 + O_2 \rightarrow 2NO$$$$2NO + O_2 \rightarrow 2NO_2$$$$NO + O_3 \rightarrow NO_...

2009 Summer

Theory

CH7 - REDOX REACTIONS

The equations represent redox reactions.In which equation is the underlined substance acting as a reducing agent?A \underline{\text{CaO}} + \text{H}_2...

2009 Winter

Theory

CH7 - REDOX REACTIONS

The equations represent redox reactions. In which equation is the underlined substance acting as a reducing agent? \( A \) \( \underline{\text{CaO}}...

2009 Winter

Theory

CH7 - REDOX REACTIONS

The distinctive smell of the seaside was thought to be caused by ozone, $O_3$. Ozone is a form of the element oxygen.(a) A mixture of oxygen and ozone...

2009 Winter

Theory

CH7 - REDOX REACTIONS

The distinctive smell of the seaside was thought to be caused by ozone, $O_3$.Ozone is a form of the element oxygen.(a) A mixture of oxygen and ozone ...

2009 Winter

Theory

CH7 - REDOX REACTIONS

The following are examples of redox reactions.(a) Bromine water was added to aqueous sodium sulfide.$Br_2(aq) + S^{2-}(aq) \rightarrow 2Br^{-}(aq) + S...

2010 Summer

Theory

CH7 - REDOX REACTIONS

(a) Bromine water was added to aqueous sodium sulfide.$$\text{Br}_2(\text{aq}) + \text{S}^{2-}(\text{aq}) \rightarrow 2\text{Br}^-(\text{aq}) + \text{...

2010 Summer

Theory

CH7 - REDOX REACTIONS

The red colour in some pottery glazes may be formed as a result of the reactions shown.heat$\text{CuCO}_3 \rightarrow \text{CuO} + \text{CO}_2$$\text{...

2010 Winter

Theory

CH7 - REDOX REACTIONS

The red colour in some pottery glazes may be formed as a result of the reactions shown.$\text{CuCO}_3 \xrightarrow{\text{heat}} \text{CuO} + \text{CO}...

2010 Winter

Theory

CH1 - STATES OF MATTER

Which diagram shows the process of diffusion?[Image_1: A, B, C, D diagrams with different atoms]

2012 Summer

Theory

CH2 - SEPARATING SUBSTANCES

Which method is most suitable to obtain zinc carbonate from a suspension of zinc carbonate in water?A) crystallisationB) distillationC) evaporationD) ...

2012 Summer

Theory

CH10 - THE SPEED OF A REACTION

A student investigates how the concentration of an acid affects the speed of reaction with a 0.5 g mass of magnesium at 30°C.The student has a beaker...

2012 Summer

Theory

CH3 - ATOMS AND ELEMENTS

An element Y has the proton number 18.The next element in the Periodic Table is an element Z.Which statement is correct?A. Element Z has one more elec...

2012 Summer

Theory

CH3 - ATOMS AND ELEMENTS

Which atom has twice as many neutrons as protons?A: $^1_1\text{H}$B: $^2_1\text{H}$C: $^3_1\text{H}$D: $^4_2\text{He}$

2012 Summer

Theory

CH4 - ATOMS COMBINING

Which is a simple covalent molecule?[Table_1]

2012 Summer

Theory

CH4 - ATOMS COMBINING

The electronic structures of atoms P and Q are shown.P and Q react to form an ionic compound.What is the formula of this compound?A. PQ2B. P2QC. P2Q6D...

2012 Summer

Theory

CH4 - ATOMS COMBINING

The diagrams show the structures of two forms, P and Q, of a solid element.What are suitable uses of P and Q, based on their structures?[Table_1]| |...

2012 Summer

Theory

CH5 - REACTING MASSES AND CHEMICAL EQUATIONS

The equation for the reaction between magnesium and dilute sulfuric acid is shown.$$\text{Mg } + \text{ H}_2\text{SO}_4 \rightarrow \text{MgSO}_4 + \t...

2012 Summer

Theory

CH1 - STATES OF MATTER

Winston Churchill, a British Prime Minister, had his false teeth electroplated with gold. The teeth were coated with a thin layer of carbon and were t...

2012 Summer