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

The diagram shows a cup of tea. Which row describes the water particles in the air above the cup compared with the water particles in the cup?[Table_1...

2010 Summer

Theory

CH2 - SEPARATING SUBSTANCES

A fruit drink coloured orange contains a dissolved mixture of red and yellow colouring agents. One of these colouring agents is suspected of being ill...

2010 Summer

Theory

CH1 - STATES OF MATTER

A student carries out an experiment to find how fast 3 cm pieces of magnesium ribbon dissolve in 10 cm³ samples of sulfuric acid at different tempera...

2010 Summer

Theory

CH4 - ATOMS COMBINING

Which row shows the change that takes place when element X gains the new particle shown?[Table_1]Table 1| | particle gained | change || --- ...

2010 Summer

Theory

CH3 - ATOMS AND ELEMENTS

The diagram shows an atom.key𝑒 electronnucleus containing nine particlesWhat is the proton number and neutron number of the atom?[Table_1]| | ...

2010 Summer

Theory

CH3 - ATOMS AND ELEMENTS

The symbols of two atoms may be written as shown.$$^{52}_{23}\text{X} \quad {}^{52}_{24}\text{Y}$$Which statement about these atoms is correct?A. They...

2010 Summer

Theory

CH14 - MAKING USE OF METALS

Which name is given to mixtures of metals?A. alloysB. compoundsC. oresD. salts

2010 Summer

Theory

CH4 - ATOMS COMBINING

Element X has six electrons in its outer shell.How could the element react?A by gaining two electrons to form a positive ionB by losing six electrons ...

2010 Summer

Theory

CH4 - ATOMS COMBINING

In which compounds are pairs of electrons shared between atoms?1. sodium chloride2. methane3. lead bromideA 1 only B 2 only C 1 and 3 D 1, 2 and 3

2010 Summer

Theory

CH5 - REACTING MASSES AND CHEMICAL EQUATIONS

Hydrogen and chlorine react as shown.What is the equation for this reaction?A. $2H + 2Cl \rightarrow 2HCl$B. $2H + 2Cl \rightarrow H_2Cl_2$C. $H_2 + C...

2010 Summer