Recent questions in Chemistry

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1 answer

The figure below shows part of the structure of a polymer. Give the name of the polymer.

asked Jun 22, 2021 in Chemistry Form 4 by anony mous

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1 answer

Analysis of a river water sample showed the presence of the following ions Ca2+, Na+, Cl− , NO3−.

asked Jun 22, 2021 in Chemistry Form 4 by anonymous

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1 answer

Water containing hydrogen carbonate, HCO3− and calcium Ca2+ ions, is said to be hard water

asked Jun 22, 2021 in Chemistry Form 4 by anonymous

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The half-life of Th is 1.9 years. If after 5.7 years the mass of Th was found to be 1.25 g. Determine the initial mass of the radioactive isotope

asked Jun 22, 2021 in Chemistry Form 4 by anony mous

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Complete combustion of one mole of an alkanol, CxHyOH gave four moles of water. (C= 12.0, H = 1.0, O = 16.0)

asked Jun 22, 2021 in Chemistry Form 3 by anony mous

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1 answer

A volume of sulphur IV) oxide gas diffused from an apparatus in 96 seconds. Calculate the time taken by an equal volume of carbon(IV) oxide to diffuse under the same conditions. (C = 12.0: O=16.0; S = 32.0)

asked Jun 22, 2021 in Chemistry Form 3 by anony mous

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1 answer

Consider the following reaction. H2S+Cl2 →2HCI+S

asked Jun 22, 2021 in Chemistry Form 2 by anony mous

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1 answer

The table gives standard reduction potentials for some half cells.

asked Jun 22, 2021 in Chemistry Form 4 by anonymous

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1 answer

State one factor that affects the preferential discharge of ions at the cathode

asked Jun 22, 2021 in Chemistry Form 4 by anony mous

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Salts may be classified as soluble or insoluble. Select from the following list a pair of compounds that can be used to prepare a soluble and an insoluble salt

asked Jun 22, 2021 in Chemistry Form 2 by anony mous

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1 answer

The table shows the elements in period 3 of the periodic table. Study it and answer the questions that follow.

asked Jun 22, 2021 in Chemistry Form 4 by anonymous

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Compound V reacts with water as shown in the following equation. V+H2O → CH3CH2CH2OH

asked Jun 22, 2021 in Chemistry Form 2 by anony mous

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6.2g of phosphorus was reacted with excess oxygen to form phosphorus( V) oxide. Determine the mass of the oxide formed. (0 = 16.0; P 31.0)

asked Jun 22, 2021 in Chemistry Form 3 by anony mous

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1 answer

Use the information in the Table to answer the questions that follow.

asked Jun 21, 2021 in Chemistry Form 3 by anony mous

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1 answer

In a certain factory, iron is extracted from the haematite ore using the blast furnace as shown in Figure 1. The other raw materials are coke, limestone and air. The melting and boiling points of iron are 1535°C and 3000 °C, respectively.

asked Jun 21, 2021 in Chemistry Form 3 by anonymous

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One of the ores of iron is haematite, Fe2O3. Give the name and formula of two other ores of iron.

asked Jun 21, 2021 in Chemistry Form 4 by anonymous

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1 answer

Some compounds such as CFCs and DDT are regarded as environmental pollutants. Give the complete names of

asked Jun 21, 2021 in Chemistry Form 3 by anony mous

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A factory uses 100 kg of ammonia each day to produce 160 kg of nitrogen(II) oxide. Calculate the percentage yield of nitrogen(II) oxide.

asked Jun 21, 2021 in Chemistry Form 3 by anonymous

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2 answers

Methane reacts with bromine as shown in the following equation. CH4(g) + Br2(g) → CH3Br(g) + HBr(g) Using the bond energies in the Table, calculate the enthalpy change, ΔH for the reaction.

asked Jun 21, 2021 in Chemistry Form 4 by anony mous

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1 answer

One of the reactions in the manufacture of nitric(V) acid involves catalytic oxidation of ammonia as shown in the equation.

asked Jun 21, 2021 in Chemistry Form 4 by anonymous

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