Molecules and Atomicity

Q. Calculate the molecular mass of water

Q.

What are the eight diatomic elements?

Q.

What is the difference between atoms, elements, molecules and compounds?

Q.

Calculate the mass of one atom of oxygen.

Q.

Define molecular formula?

Q.

What is element and compound?

Q. In the universe how many states of matter are there ?name the matter !in addition to solid, liquid and gas

Q.

What is meant by atomicity? Explain with two examples.

Q. Hydrogen sulphide contains 94.11% sulphur, sulphur dioxide contains 50% oxygen and water contains 11.11% hydrogen. Show that these figures are in agreement with law of reciprocal proportions.

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A substance X is highly compressible and could easily be liquefied. It could also take the shape of the container. Predict the nature of the substance. List any two properties of substance X other than those already mentioned.

Q.

What is the difference between $2H$ and $H_2$?

Q. What is the molecular mass of H2

Q. How many moles of calcium carbonate are present in 10g of the substance?

Q.

What is the difference between 2H and H2?

Q.

A solution turns blue litmus red. The pH of the solution is probably

1. 8

2. 10

3. 12

4. 6

Q.

Give reason- A gas filled completely the vessel in which it is kept

Q.

What is meant by atomicity ? Name a diatomic element.

Q.

Classify each of the following on the basis of their atomicity. $\left(\mathrm{a}\right){\mathrm{F}}_2\left(\mathrm{b}\right){\mathrm{NO}}_2\left(\mathrm{c}\right){\mathrm{N}}_2\mathrm{O}\left(\mathrm{d}\right){\mathrm{C}}_2\mathrm{H}{}_6(\mathrm{e}){\mathrm{P}}_4(\mathrm{f}){\mathrm{H}}_2{\mathrm{O}}_2(\mathrm{g}){\mathrm{P}}_4{\mathrm{O}}_{10}(\mathrm{H}){\mathrm{O}}_3(\mathrm{i})\mathrm{HCl}(\mathrm{j}){\mathrm{CH}}_4(\mathrm{k})\mathrm{He}(\mathrm{l})\mathrm{Ag}$

Q.

Argon has atomic number of 18 and mass number of 40. Calcium has atomic 20 and mass number 40. Calcium and argon are examples of

1. isotopes

2. isochores

3. isobars

4. isotones

Q.

Explain the difference between 2N and $N_2$.

Q.

Calculate the mass of 0.72 grams molecule of carbon dioxide

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Define atomicity. What will be the atomicity of ozone and ammonia? [2 MARKS]

Q. Name the anion and cation which constitute the molecule of magnesium oxide.

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What is a diatomic molecule?

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What is the difference between an atom of hydrogen and a molecule of hydrogen?

Q. How many grams of magnesium will have the same number of atoms as 6 grams of carbon?

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What is variable compositions?

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Matter was believed to be continuous like a block of wood. What does the word continuous mean here and how it is related to the block of wood?

Q.

Question 18
State the number of atoms present in each of the following chemical Species

(a) $C{O}_3^{2-}$

(b) $P{O}_4^{3-}$

(c) $P_2{O}_5$

(d) $CO$

Q.

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

1. Oxygen

2. Nitrogen

3. Chlorine

4. Neon