IGCSE Chemistry: Specimen Questions with Answers 97 - 99 of 240

Question 97

Write in Short Short Answer▾

A sealed tube containing an equilibrium mixture of nitrogen dioxide and dinitrogen tetroxide was placed in a beaker of ice cold water. The color of the mixture changed from brown to pale yellow.

Is the forward reaction exothermic or endothermic? Give an explanation for your choice.

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Explanation

Type of this reaction is exothermic because when this reaction happens then 57.2 J

  1. Sulfuric acid and malonic acid are both dibasic acids. One mole of a dibasic acid can form two moles of hydrogen ions.

Question 98

Write in Short Short Answer▾

How could you determine if a sample of malonic acid is pure?

result if pure [2 Marks]

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Explanation

If malonic acid is pure then it starts melting else it will not.

Question 99

Question MCQ▾

Element X is represented by

Which statement about element X is correct?

Choices

Choice (4)

a.

An atom of X contains protons and neutrons

b.

An atom of X contains protons and electrons

c.

X forms an ion by gaining electrons

d.

X is placed in Group III of the Periodic Table

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Answer

d.

Explanation

Correct option is D because X represent Aluminium and In periodic table Aluminium is placed in group III.

Its atomic number is and It is a silvery-white, soft, nonmagnetic, ductile metal in the boron group. As shown in figure.

Periodic Table