NECO SSCE - Chemistry - 2003

Chlorine is used in water purification because it

What change will occur during the electrolysis of brine using carbon electrodes?

Which formula is used to indicate the degree of acidity of an acid?

What is the number of moles of NaHCO₃in 250cm³ of its solution if the solution contains 8.4 g of NaHCO₃ in 1 dm³ of the solution. [Na = 23, 0 = 16, C = 12, H = 1)

What change will occur to the equilibrium mixture
\( 2CrO^{2-}_4(aq) + 2H^+(aq) ⇔ Cr_2O^{2-}_7(aq) + H_2O(l) \) when excess sodium hydrogen solution is added?

Which metal is extracted from bauxite?

Which separation technique is routinely applied in the petroleum industry?

Which method is used for the purification of copper from its ore?

Which metal is a constituent of both bronze and solder?

In the reaction 2H₂S(g) + SO₂(g) → 2H₂SO(I)+3S(s)SO₂is acting as _agent

A calcium atom and a calcium ion have the same

How many Faradays of electricity are required to liberate 9g of aluminium? [Al = 27]

Which compound will give propane when it Is dehy drated by an excess of hot, concentrated tetraoxosvlphate(VI) acid?

Which metal bromide is widely used in photography?

Small amounts of compounds of transition metals are sometimes added to glass during manufacture in order to make the glass

Which statement is NOT true about the composition of starch?

Naturally occurring lithium consists of 90% \( ^7_3Li \text{ and 10% } ^6_3 Li. \) What is the relative atomic mass of lithium?

Which hydrocarbon does NOT exhibit structural isomerism?

What mass of silver is deposited when a current of 2.6 A is passed through a solution of a silver salt for 40 minutes? [Ag= 108 ; F=96500C]

The boiling point of water is higher than the boiling point of ethanol because

What is the concentration (in mol dm³) of a solution containing 28 g of potassium hydroxide per 100 cm³ of solution? (K=39; H=1; 0=16)

Why is tetraoxosulphate(VI) acid NOT used for making carbon dioxide from calcium carbonate? It is

What mass of copper is deposited when 6.5g of granulated zinc reacts with excess copper(II) tetraoxosulphate(VI) solution?

The equation for the reaction is: Zn(s) + \( CuSO_4(aq)→ ZnSO_4(aq)+ Cu(s)\)[CU= 64; Zn=65]

At s.t.p, a mole of chlorine occupies 22.4dm³. If the temperature is changed to 35°C and the pressure to 750mHg the of the new volume will be [Cl = 35.5]

Which element is the most electronegative?

What is formed when starch is completely hydrolysed?

Which is NOT a synthetic polymer?

The reaction C₂H₆ → C₂H + H₂ is known as

What is the IUPAC name of CH₃CCI=C(CH₃)2?

Why does the treatment of cotton fabrics with dilute acids weaken the materials?

The number of hydrogen ions in 1.0dm6.00x10³ of a 0.25 mole dm6.00x10^-3 tetraoxosulphate(Vl) acid solution is
[Avogadro constant = 6.0 x 1 0]

An atom of element X has an electronic configuration of \( 1s^22p^33s^23p^2. \) In which group of the periodic table is X?

The pH of water is 7.

What is the pH of orange juice?

B is an isotope of the element \(^{238} _{92}Ur\). The isotope B has

An organic compound gave the following results on analysis: C = 29.3% ; H = 5.7%; Br = 65%.
What is the empirical formula of the compound? [C = 12, H = 1, Br=80]

Ethene decolourises acidified potassium tetraoxomanganate(VII) solution. Which gas will decolourise bromine water?

What is the change in the oxidation number of phosphorus in the following reaction?

4P(s) + 5O₂(ag) → 2P₂O₅(s)

Chlorine displaces bromine from aqueous potassium bromide because