NECO SSCE - Chemistry - 2003

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

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]

Which element is the most electronegative?

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]

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

Which metal bromide is widely used in photography?

Which is NOT a synthetic polymer?

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]

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]

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?

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

Which metal is extracted from bauxite?

Which metal is a constituent of both bronze and solder?

Chlorine is used in water purification because it

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

Which hydrocarbon does NOT exhibit structural isomerism?

Which separation technique is routinely applied in the petroleum industry?

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)

Chlorine displaces bromine from aqueous potassium bromide because

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

A calcium atom and a calcium ion have the same

What is formed when starch is completely hydrolysed?

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

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

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)

The reaction C₂H₆ → C₂H + H₂ is known as

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

4P(s) + 5O₂(ag) → 2P₂O₅(s)

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

Which statement is NOT true about the composition of starch?

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

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

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

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

The pH of water is 7.

What is the pH of orange juice?

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

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]

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

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