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The number of protons in a sodium atom is:
جواب دیکھیں
درست جواب: 11
The atomic number of sodium is 11.
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The number of electrons in a chloride ion (atomic number 17) is:
جواب دیکھیں
درست جواب: 18
The ion has gained one electron.
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Boyle's law relates the pressure of a gas to its:
- 1 Temperature at constant volume
- 2 Density at constant pressure
- 3 Volume at constant temperature
- 4 Mass at constant volume
جواب دیکھیں
درست جواب: Volume at constant temperature
P₁V₁ = P₂V₂ at constant temperature.
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According to Charles's law, the volume of a fixed mass of gas at constant pressure is proportional to:
- 1 Its pressure
- 2 Its absolute temperature
- 3 Its density
- 4 Its mass
جواب دیکھیں
درست جواب: Its absolute temperature
V ÷ T is constant when T is in kelvin.
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The molar mass of sulfuric acid, H₂SO₄ (H = 1, S = 32, O = 16), is:
- 1 96 g/mol
- 2 82 g/mol
- 3 98 g/mol
- 4 64 g/mol
جواب دیکھیں
درست جواب: 98 g/mol
2 + 32 + 64 = 98.
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The number of moles in 4.9 g of sulfuric acid (molar mass 98 g/mol) is:
جواب دیکھیں
درست جواب: 0.05
4.9 ÷ 98 = 0.05.
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The empirical formula of glucose, C₆H₁₂O₆, is:
- 1 C₂H₄O₂
- 2 CH₂O
- 3 C₆H₁₂O₆
- 4 C₃H₆O₃
جواب دیکھیں
درست جواب: CH₂O
The simplest ratio of the atoms is 1 : 2 : 1.
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The pH of a 0.001 M solution of hydrochloric acid is:
جواب دیکھیں
درست جواب: 3
pH = −log 0.001 = 3.
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A buffer solution is a mixture of:
- 1 A weak acid and its salt
- 2 Water and a salt
- 3 Two strong acids
- 4 A strong acid and a strong base
جواب دیکھیں
درست جواب: A weak acid and its salt
The pair resists a change of pH.
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A reaction is spontaneous at constant temperature and pressure when:
- 1 ΔG is positive
- 2 ΔG is negative
- 3 ΔH is positive
- 4 ΔS is zero
جواب دیکھیں
درست جواب: ΔG is negative
A negative change in free energy means that the process can occur.
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A reaction has the rate law rate = k[A]². The order of the reaction is:
- 1 Zero
- 2 Third
- 3 First
- 4 Second
جواب دیکھیں
درست جواب: Second
The order is the sum of the powers of the concentrations.
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In the electrolysis of molten sodium chloride, sodium is formed at the:
- 1 Salt bridge
- 2 Cathode
- 3 Anode
- 4 Electrolyte surface
جواب دیکھیں
درست جواب: Cathode
Sodium ions gain electrons at the cathode.
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In an electrochemical cell, oxidation takes place at the:
- 1 Cathode
- 2 Salt bridge
- 3 Voltmeter
- 4 Anode
جواب دیکھیں
درست جواب: Anode
Oxidation is loss of electrons at the anode.
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Which reagent is decolourised by an alkene?
- 1 Copper sulfate solution
- 2 Limewater
- 3 Bromine water
- 4 Litmus solution
جواب دیکھیں
درست جواب: Bromine water
The bromine adds across the double bond.
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The IUPAC name of CH₃CH=CH₂ is:
- 1 Propane
- 2 Propyne
- 3 Propene
- 4 Butene
جواب دیکھیں
درست جواب: Propene
The three carbon chain with a double bond is propene.
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Ethanol and dimethyl ether, both C₂H₆O, are examples of:
- 1 Functional group isomers
- 2 Optical isomers
- 3 Chain isomers
- 4 Position isomers
جواب دیکھیں
درست جواب: Functional group isomers
They have the same formula but different functional groups.
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Benzene reacts with a mixture of concentrated nitric acid and sulfuric acid to give:
- 1 Chlorobenzene
- 2 Phenol
- 3 Nitrobenzene
- 4 Cyclohexane
جواب دیکھیں
درست جواب: Nitrobenzene
This is the nitration of benzene.
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Aldehydes can be tested with:
- 1 Litmus paper
- 2 Tollens' reagent
- 3 Limewater
- 4 Bromine water
جواب دیکھیں
درست جواب: Tollens' reagent
An aldehyde forms a silver mirror with Tollens' reagent.
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The hybridisation of the carbon atoms in ethyne (C₂H₂) is:
جواب دیکھیں
درست جواب: sp
Each carbon has a triple bond and one other single bond.
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The bond angle in a water molecule is about:
- 1 104.5°
- 2 180°
- 3 109.5°
- 4 120°
جواب دیکھیں
درست جواب: 104.5°
The two lone pairs reduce the angle from 109.5°.
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The high boiling point of hydrogen fluoride compared with hydrogen chloride is because of:
- 1 A lower molar mass
- 2 Metallic bonding
- 3 Hydrogen bonding
- 4 Ionic bonding
جواب دیکھیں
درست جواب: Hydrogen bonding
Hydrogen fluoride forms hydrogen bonds.
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Going down a group of the periodic table, the first ionisation energy usually:
- 1 Decreases
- 2 Stays the same
- 3 Doubles
- 4 Increases
جواب دیکھیں
درست جواب: Decreases
The outer electron is further from the nucleus.
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Which of these is a Lewis acid?
جواب دیکھیں
درست جواب: BF₃
BF₃ can accept a pair of electrons.
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The catalyst used in the Haber process for ammonia is:
- 1 Nickel
- 2 Iron
- 3 Vanadium pentoxide
- 4 Platinum
جواب دیکھیں
درست جواب: Iron
Finely divided iron is the catalyst.
غلطی کی اطلاع دیں
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Which gas is mainly responsible for acid rain?
- 1 Nitrogen
- 2 Sulfur dioxide
- 3 Helium
- 4 Argon
جواب دیکھیں
درست جواب: Sulfur dioxide
Sulfur dioxide forms sulfurous and sulfuric acid in water.
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