EASY

9th CBSE

IMPORTANT

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Which of the following elements has the same molecular mass as its atomic mass?

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Important Questions on Atoms and Molecules

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9th CBSE

IMPORTANT

Science for Ninth class Part 2 Chemistry>Chapter 3 - Atoms and Molecules>Multiple Choice Questions (MCQs)>Q 72

In water, the proportion of oxygen and hydrogen by mass is :

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9th CBSE

IMPORTANT

Science for Ninth class Part 2 Chemistry>Chapter 3 - Atoms and Molecules>Multiple Choice Questions (MCQs)>Q 73

In hydrogen peroxide (H₂O₂), the proportion of hydrogen and oxygen by mass is:

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9th CBSE

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Science for Ninth class Part 2 Chemistry>Chapter 3 - Atoms and Molecules>Multiple Choice Questions (MCQs)>Q 74

The symbols of the elements cobalt, aluminium, helium and sodium respectively written by a student are as follows. Which symbol is the correct one?

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9th CBSE

IMPORTANT

Science for Ninth class Part 2 Chemistry>Chapter 3 - Atoms and Molecules>Questions Based on High Order Thinking Skills (HOTS)>Q 75

Copper sulphate reacts with sodium hydroxide to form a blue precipitate of copper hydroxide and sodium sulphate. In an experiment, $15.95 g$ of copper sulphate reacted with $8.0 g$ of sodium hydroxide to form $9.75 g$ of copper hydroxide and $14.2 g$ of sodium sulphate. Which law of chemical combination is illustrated by this data? Give reason for your choice.

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9th CBSE

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Science for Ninth class Part 2 Chemistry>Chapter 3 - Atoms and Molecules>Questions Based on High Order Thinking Skills (HOTS)>Q 76

Potassium chlorate decomposes on heating, to form potassium chloride and oxygen. When $24.5 g$ of potassium chlorate is decomposed completely, then $14.9 g$ of potassium chloride is formed. Calculate the mass of oxygen formed. Which law of chemical combination have you used in solving this problem?

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9th CBSE

IMPORTANT

Science for Ninth class Part 2 Chemistry>Chapter 3 - Atoms and Molecules>Questions Based on High Order Thinking Skills (HOTS)>Q 77

In an experiment,

4.90 g

of copper oxide was obtained from

3.92 g

of copper. In another experiment,

4.55 g

of copper oxide gave, on reduction,

3.64 g

of copper. Show with the help of calculations that these figures verify the law of constant proportions.

MEDIUM

9th CBSE

IMPORTANT

Science for Ninth class Part 2 Chemistry>Chapter 3 - Atoms and Molecules>Questions Based on High Order Thinking Skills (HOTS)>Q 78

Magnesium and oxygen combine in the ratio of

3 : 2

by mass to form magnesium oxide. What mass of oxygen gas would be required to react completely with

24 g

of magnesium?

EASY

9th CBSE

IMPORTANT

Science for Ninth class Part 2 Chemistry>Chapter 3 - Atoms and Molecules>Questions Based on High Order Thinking Skills (HOTS)>Q 79

When

5 g

of calcium is burnt in

2 g

of oxygen, then

7 g

of calcium oxide is produced. What mass of calcium oxide will be produced when

5 g

of calcium is burnt in

20 g

of oxygen? Which law of chemical combination will govern your answer?

Which of the following elements has the same molecular mass as its atomic mass?

Important Questions on Atoms and Molecules

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